No matter what you drive...
you'll be glad you found us!

Independent Service for:
Acura
Audi
BMW
Buick
Cadillac
Chevrolet
Chrysler
Dodge
Ford
Geo
GMC
Honda
Hummer
Infiniti
Jaguar
Jeep
Land Rover
Lexus
LINCOLN
Mazda
Mercedes
Mercury
MINI
Mitsubishi
Nissan
Oldsmobile
Plymouth
Pontiac
Porsche
Range Rover
Saab
Saturn
Scion
Subaru
Suzuki
Toyota
Volkswagon
Volvo

 

We are at the intersection of
Quality Service
&
Satisfied Customers.

 

Providing Customer Satisfaction since 1985!    See what others say.

"Guaranteed Service Results!"

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Professional Automotive Repair

Import and Domestic Parts and Service

Providing Customer Satisfaction since 1985

3 Locations in Atlanta

Index

1. Marietta
        Staff
2. Alpharettta
        Staff
3.  Midtown
        Staff
4.  Company History
5.   Still in Warranty?
6.   Technical Expertise
7.    Scope of services
8.    Out of warranty
9.    What should I budget?
10.   The Half-Million Mile Volvo
11.   Check Engine Light
12.   How often should I change my oil?
13.   A Service Versus An Oil Change
14.   Automatic e-mail Service Reminder
15.   Major Service
16    Full Service
17.   Intermediate Service
18.   Minor Service
19.   Prioritized Needs List
20.   What does a Tune-up consist of?
21.   Timing Belts
22.   Used Car Pre-Purchase Evaluation Report
23.   Disk Brakes 101
24.   Automotive A/C Systems
25.   Behind the scenes

 

Marietta – East Cobb
1770 Lower Roswell Rd. 30068 770-509-7900
Open 8:00 AM until 6:00 PM, Monday through Friday
e-mail: volprorep1@bellsouth.net
After hours drop-off and 24 hour wrecker available
Marietta Wrecker Service 770-953-1176
For your convenience, towing charges will be added to your repair bill when you pick up your car
Online Driving Directions from Mapquest
Atlanta Traffic conditions from the Ga. DOT

Marietta Staff:

Phillip Reeves has been with us since 2004. But he is not new to Volvo! He spent the previous 7 years running a shop for one of our competitors. We are very pleased to have him with us now. He brings a large set of skills and Volvo knowledge to our Marietta shop.

Chris is the return member of our team.  He started with us in 1986 and worked with us until 1988 and then returned in early 2005.  During the period he was gone he worked at Chris Volvo as a technician and worked his way up to shop foreman.  After the dealership changed hands he finally agreed to return to work with us.  We are glad to have him back!  He has 24 years experience as a technician with 20 years on Volvos.

At 23 years, Bill is Professional Repair's most senior employee. He started with us during our 2nd month in business in 1985. Prior to that Bill worked as a Volvo dealer technician for 3 years in Savannah. As of 2007, he has a total of over 24 years of Volvo experience! We are proud of him at Professional Repair.

Mike Heaton, our newest staff member, comes to us with over 25 years of experience.  After Graduating with an associates degree in automotive from Marietta/Cobb VoTech (Now Chattahochee Technical school) in 1982, he has since achieved a masters rating in Volvo, Saab, and ASE.  He is shown here using the ever more common tool for auto repair, the PC.

 

Alpharetta - Roswell
421 South Main Street (Hwy. 9) Alpharetta, Ga 30004
770-442-9451
Open 8:00 AM until 6:00 PM, Monday through Friday
e-mail: volprorep2@bellsouth.net
After hours drop-off and 24 hour wrecker available

 

Alpharetta Staff

'Woody" Woodworth has worked as an automobile technician for 18 years and has been with Professional Repair for over 12 years!

James Hootman has worked with the Volvo product for the entire 26 years he has been in the automobile industry. He has been with Pro Repair for 17 of those years as of 2006! He has worked as a technician as well as a manager so his background is well rounded!

Robert Spruill has worked as an automobile technician for 28 years and on Volvos for the last 23 years. He has been with Professional Repair for over 14 years!

 

Midtown Atlanta
2185 Monroe Dr. Atlanta, Ga. 30324
404-875-3900
Open 8:00 AM until 6:00 PM, Monday through Friday
e-mail: volprorep3@bellsouth.net
After hours drop-off and 24 hour wrecker available
Highland Wrecker Service 678-878-9402
For your convenience, towing charges will be added to your repair bill when you pick up your car

Midtown Staff

 

 

Who we are:

Professional Repair has served Atlanta's Volvo owners for over 21 years. Founded in 1985 by a former Technical Instructor for the Volvo factory, Professional Repair has grown into a chain of 3 shops that service Import and Domestic cars, with a special emphasis on Volvos. With over 3000 Volvo customers, we represent the largest Volvo service operation in the Atlanta area after the dealerships.   We serviced Volvos exclusively for 20 years and then in early 2006 we began offering routine service and minor repairs for all makes of cars, light trucks, & SUVs.   This was in response to many requests from our customers to work on their other cars in addition to their Volvos.

The basis of your success...

Our company mission statement summarizes our philosophy. " Our goal is to provide the best possible TECHNICAL SERVICE and the best possible CUSTOMER SERVICE to car owners in the Atlanta market at a FAIR PRICE." Please note our three separate focus points: technical service, customer service, and fair price.

Our commitment to Customer Service is obvious the moment you enter our facilities. Our stores are clean, well lit, and inviting. We offer comfortable waiting areas with cable TV, free coffee, water, & sodas, Internet access, and open access to our shop areas to see first hand the work we perform. We have an appointment schedule that ensures your car gets prompt attention when you arrive. We also offer after hours drop off and pick up.

We chose to have multiple locations rather than grow a single, ever larger, store. The first reason for this is to assure you never become just another job order in a large, faceless organization. Our customers enjoy a personal relationship with our Managers and Technicians. The Techs who work on your car will even ride with you to observe your service concerns first hand if necessary. The second reason we have multiple shops is to be more convenient to our customers where they live and work. Work done at any location is guaranteed at all 3 stores.

Professional Repair offers one stop convenience for your car needs. As well as normal repairs and services, we offer tires, balancing, front end alignments, A/C service, Emission System Repairs, headliners and other interior repairs, batteries, accessories, transmission services, plus over the counter parts for most vehicles.

What if your car is still in Warranty?

Professional Repair can perform the routine services required to maintain your factory warranty, reset your service light, and stamp your service records. All of our work is performed to factory standards using first quality materials.

What about our Technical Expertise?

Our continuing commitment to technical proficiency is shown by our purchase of computer based diagnostic equipment specific to the newer Volvo products. This diagnostic equipment represents an investment of over $6,000 per store for the hardware alone. Operating software from Volvo is by annual subscription. It costs nearly $7,000 per store, per year! This service information system is known as VIDA and is the same system used by Volvo dealers (details at https://www.volvotechinfo.com/index.cfm?event=info.subscriptions.pricing.pricingAioc).

Each store also subscribes to VDA (Volvo Diagnostic Application) and WSDA (Web Software Download Application), which are also required to service any 1999 or newer model Volvo fully. Each of these represent additional charges per store, per year.

Without these costly programs a shop CANNOT fully diagnose and service 1999 or newer model Volvos. Obviously, only a shop that has a strong client base in Volvos can afford to even consider this type of investment. This is an example of how committed we are to continuing to offer the best Technical Service possible!

Non-Volvo cars...

We have also invested in a number of generic diagnostic tools and information systems to service most other cars.   While we can't offer the depth of heavy repairs that we do on Volvos we still can perform 80-85% of   routine services and light repairs on most makes of cars and trucks.

 

We have serviced Volvos for over 21 years however, we are now servicing most* makes of cars, light trucks, and SUVs!
Here is why-

My name is Clarke Otten and I am the owner of the former Professional Swedish Car Repair, also often called Volvo Professional Repair.  I started my business over 21 years ago.  Like all entrepreneurs I planned to grow my business over the years.  However, I never allowed my desire for growth to surpass my desire for maintaining the highest quality in technical expertise and customer service. 

Over the years I have learned many things.  One, is that 3 is the optimal number of shops that I can oversee effectively.  Another thing I have learned is that with 3 shops I can get a good �average� benchmark of performance to hold all the stores against.

One of these benchmarks has proven to be that there is a limit to how many Volvo owners I can expect to capture for a given geographical area.  If I want to grow my business any larger I must expand into additional  market areas.  Knowing 3 shops is my optimum number, and that I have reached maximum market penetration with Volvo owners within my current market areas, I have been faced with the conundrum of how to grow my business.

Then I realized that many of my customers had been giving me the answer for years when they asked if we could work on their other cars!  In the past I have always said �Sorry, since we can't be an expert at all products the same way we can by focusing on just Volvos, we have chosen to be the very best at Volvos and ignore the rest�.  No more!   

Since 75-85% of most service work on any make of car doesn't call for extremes of expertise, training, and equipment we have changed our business model.  As long as we don�t try to spread ourselves too thin by trying to be an absolute expert on all makes of cars we can still do the majority of minor repairs and services that most cars need while keeping our focus on being the best there is in the Volvo field.

In March, 2006 we began to offer service for your other vehicles at our Marietta and Alpharetta stores.  Work can performed at either store by appointment or drop in.  Sorry, but size limitations at our Midtown store keep us from offering more than very basic services on other makes at that location yet.  We hope to have our expansion at the Midtown store done by Fall 2007.  Then we will be able to offer more services on most makes.

This new business plan has become so successful with both our existing customers and new ones alike that we are re-branding our company from "Professional Swedish Car Repair" to simply "Professional Automotive Repair".  The same people, just a new name.

You already know our commitment to integrity, honesty, and fair pricing.  We can now give you that commitment for most services you might need on your other cars as well.  Give us a try and see!

*Due to physical the size limitations of our shops and lifts we can�t accommodate vehicles larger than 6000lbs GVW.

I am out of warranty now.  Is it necessary to continue to perform all my services the way I needed to do to maintain my factory warranty eligibility?

Warranty eligibility was only one of the reasons for performing any brand of vehicle's recommended preventative maintenance services on your car. The biggest reason was, and will remain to be, to make your investment in your vehicle last as long as possible. Even if you do not plan to keep your car through its complete life span, following the service schedule will help uphold its maximum resale value.

If you have an extended warranty policy most companies require that you continue to follow the factory schedule!

The older your car gets the more important regular checkups become, just like the older we get the more important the care of ourselves through proper diet and exercise becomes. You can get by with skipping meals, workouts, etc.  much easier when you are 25 years old than you can when you are 45 years old. The same is true with keeping up with your car services. The most important service is a regular oil and filter change, using a high quality oil filter (not a cheap off-brand) and high quality oil every three months or 3,000-3,500 miles.  Most quickie oil change facilities use the cheapest oil and filters available.  They also do not have the expertise to notice potential other problems your car may have which could cause you to have a breakdown.

What should I budget to keep my older Volvo (or other car) in top shape and well protected?

Having specialized in Volvo for over 21 years, we are frequently asked this.  Repeated analysis of our long-term customer files shows that over a three year or 75,000 mile period you can expect to spend approximately $1,800-$2,400 per year or $150-$200 per month. This is far cheaper than new car payments!  The expenses, of course, do occur evenly. There are months were nothing is spent and others where large amounts are spent. This figure includes maintenance, repairs, and tires but does not include taxes, tag, or insurance expense. Of the latter three, these go down over time, which is another incentive for keeping your older model Volvo (or any other make for that matter) running well for as long as possible.

Speaking of insurance, if you are making the investment to keep your car long term you should also consider the amount you insure the car for. We have many customers with over a quarter of a million miles whose cars are still reliable, safe transportation. However, most insurers will assign a very low value to these cars because of their mileage. As a result, after a small accident, often one where the car is still drivable, the insurance companies will want to total the car and give you a small sum that would barely cover one years maintenance costs, much less the true replacement value for your car. Therefore, we suggest that you protect your investment by establishing a fixed value for your car of 2-3 times what your insurance company would normally say your car is worth. The extra premium for insuring your car, for say $6,000 vs. $2,000, will be very small and will protect your investment in keeping the car well maintained. Talk to your insurance agent about this. If your insurer does not offer a fixed value policy then we suggest you shop for a different carrier!

 

The Half-Million Mile Volvo

Regular maintenance has kept this Volvo going
strong on the same engine for over 1/2 million miles!

Steve and Susan Schirm's half million mile plus Volvo at our Marietta shop

Update 2007:  Now over 600,000 miles!

 

Check Engine Light

What does it mean?

In the late 1980's the Federal Government decided cars should be equipped with a warning light for any condition that might cause your car to have higher than normal emissions. This was the start of the "OBD" (On Board Diagnostic system) and the "Check Engine" light. At first, these programs were crude and unreliable. Often the light would turn on with no evident fault in the car.  A " False Alarm" . You could reset the light and maybe it would come on again and maybe not.

In 1996 the monitoring systems became more sophisticated and would give fairly reliable Diagnostic Trouble Codes (DTC) codes when the Check Engine light came on. This newer system is known as the OBD-II (On Board Diagnostic system, level two). Most of the DTCs (Diagnostic Trouble Codes) in these systems are accurate. But not all the time! Once again, in the case of a " False Alarm" you could reset the light and maybe it would come on again and maybe not.

Your Check Engine light does not usually indicate there is a " crisis" that could leave you stranded.   However, you should check your temperature gauge for overheating (if equipped) and check your engine oil level just to be safe.   The Check Engine light only comes on for conditions that could lead to higher emissions.   Most of these conditions do not reflect the reliability of the car to run.   Conversely, your engine could have serious problems that need immediate attention and the Check Engine light will  not come on because the problem doesn't effect your emissions.   For example you could be nearly out of oil or coolant and these will not trigger a Check Engine light because your emissions are still OK, right up until the point the engine self destructs.   An engine that does not run never creates air pollution.  Remember pollution, not mechanical condition,  is what the Check Engine light is monitoring.

Please note on OBD-II cars if the Check Engine light is on you will fail the emissions test automatically even if it is a false alarm!

The cost of reading the DTCs and resetting the light (without repairs) on the early cars (OBD) is:

$45 service charge

The cost of reading the DTCs and resetting the light (without repairs) on the later cars (OBD II)is:

and a
$47.50 service charge

In either case, if you elect to perform the repairs necessary the diagnostic charge will be waived.

Contact the store nearest you to get your check engine light diagnosed:

Marietta
Alpharetta
Midtown

 

How often should I change my oil?

The rule of thumb is every 3 months or 3,000-3,500 miles whichever comes first. The main reason for changing your oil is not that the oil has worn out but that it has become contaminated.

Every time you shut off your car off, during the split second of shut down, a small amount of fuel is delivered to the cylinders which does not get burned. This gasoline seeps past the rings and into the crankcase oil. Next time you start your car and bring it to operating temperature for 10 minutes or more that gasoline evaporates out of the oil and is drawn into the engine through the PCV (positive crankcase ventilation) system and is burnt.

However, if most of what you do is a series of short trips of less than 10 minutes each the oil never gets hot enough to boil off the gasoline and the oil becomes diluted to the point its ability to protect your engine is severely compromised. You can check for this condition by smelling the oil on your dipstick. It should not smell of gasoline! Nor should it smell burned. If either situation exists you should change your oil.

The other form of contamination is partially burnt carbon compounds or ash. These build up over time and are not a problem as long as the oil is changed regularly. If you do not change it these will build up in your engine and clog oil passageways and even block the oil pickup tube in the engine eventually. You can check for this type of contamination by inspecting the engine side of your oil filler cap. It should have a dark brassy yellow color with no clumps of black deposits.

The other important item in the oil change is the filter. ALWAYS, always, use a Factory  brand oil filter, not just any filter that "fits" your Car. With Volvo not only does the VOLVO filter have superior filter paper and a large flow capacity for high speed, Volvo incorporates a check valve in their oil filter that traps oil throughout the engine when you shut off the car. This prevents the oil from draining back down to the sump while the engine is off. That way, when you start your car, oil is already everywhere it is needed. Most after-market filters (with very, very few exceptions) do not have this check valve. Every time you start your engine it has to prime all the oil passageways once again. You may even notice that the oil light does not go out immediately once the engine has started. This is because the engine can't develop oil pressure until the passageways are filled once again. This creates severe wear on the engine with every crank up.

We always use VOLVO oil filters  (or an appropriate equivalent on other makes) at our stores.

The best way to keep up with your total service needs, including oil changes, is to follow the service schedule in your owner's manual and use high quality oil and filters.

Most quickie oil change facilities use the cheapest oil and filters available.  They also do not have the expertise to notice potential other problems your car may have which could cause you to have a breakdown.

Welcome to our electronic communications page!

Thanks to the Internet age we can simplify your life by automatically helping you remember when your car needs servicing.

Most drivers in Atlanta drive in what are considered "Severe" driving conditions. Stop and go traffic of the worst kind, where everyone accelerates full speed to the next stop point and brakes sharply at the last minute.  A commute from Macon to Savannah every day would not be as hard on your car as Atlanta traffic is.  It is important to keep your car routinely serviced to prevent unscheduled car problems.  Being stuck on the side of the road is no fun!  

At the minimum, change the oil, check the tires, brakes, lights, and other safety items every 3 months or 3,000-3,500 miles.  Very few drivers who use our shops have driving habits that make going longer between service checks a prudent behavior.  If you are unsure how best to determine what your service interval is click here.

To have us notify you by e-mail simply fill in the following form.  If you have more than one car you would like us to keep up with then fill out this page once for every car.

A Service Versus An Oil Change

Many people have asked  us "What is the difference?  It looks to me like a "Service"
is just an oil change with a lot of extra labor expense. is there any is there any difference ?

There is a big difference! Volvo has varying service requirements at different mileages. All of these services include an oil change. All Volvos fall under a 5,000 mile service interval or a 7,500 mile service interval. At Professional Repair we characterize these different services as either a major service, a full service, or an intermediate service. Each of these vary in cost and scope of work.

To see what our Major Service includes click here.

To see what our Full Service includes click here.

To see what our Intermediate Service includes click here.

Volvo further recommends more frequent oil changes in between regularly scheduled services when driving under "Adverse Conditions". See your owner's manual for a definition of "Adverse Conditions". Sum up all the various conditions and you will discover that "Adverse" is just about any time the wheels are turning!

We refer to this "in between" oil change as a Minor Service.

>To see what our Minor Service includes click here.

If you have looked at the links for our services you will have seen that a service includes checking, adjusting, & lubricating many systems on your car. Once the technician finishes this check list the Service Manager will call you with a prioritized needs list including prices for any additional work that may be needed. No additional work is ever done without a customers prior consent.

What do you mean by a prioritized needs list?

The technician will list anything that is even slightly worn or leaks on your car. In terms of leaks we rate our leaks from 1 to 5 in severity. A "1" shows dampness and indicates a very minor leak that should be monitored on upcoming visits and during your own fluid level checks. A "5" will need repairs as soon as possible. Most possible fluid leaks from your car only occur while the engine is running and therefore will not leave any large puddles in your driveway, maybe only a few small spots at most.

Brakes are gauged on a percentage of the pads left. We recommend that pads be changed when they reach the 15-20% range. Leaving them on the car below this point increases the chance of warped brake rotors which will increase the cost of repair. Often we will note that your pads will need replacing by your next oil change so you can budget for this eventuality.

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Other items starting to show wear often do not need immediate attention but we will bring them to your attention so you can plan for the upcoming expense on subsequent visits.

This future needs list is then entered into our computer so that we will be reminded to re-check items that need monitoring the next time you come in for whatever reason, even if you have forgotten about them. But to help you remember, a printed version of the list is given to you when you pick your car up.

This information becomes part of your complete service records which we keep on file at our store. If you lose a copy of a record, we can replace it. Need a copy for a repair that should be under our store warranty (1 year /15,000 miles on most items)? Don't worry, we have one on file already.

More on Services

What does a Tune-up consist of?

Many people refer to a "service" as a "tune-up". Professional members of the automotive industry generally shy away from using the term "Tune-Up" because it is poorly defined. The term usually means an ENGINE service which at one time included things like replacing spark plugs and plug wires, points and condenser, changing the air filter, adjusting valves, checking and adjusting engine timing and fuel mixture. However, modern engines with computer control systems have eliminated things like adjusting fuel mixture or ignition timing. Newer engines with hydraulic lifters no longer require valve adjustments! Electronic ignition systems don't use points and condenser. In fact, the newer Volvos don't even have spark plug wires anymore!

Engines must still be serviced though. Volvo requires an engine service or "tune-up" every 30,000 miles. And although the newer engines do not have many of the service parts and adjustments of the older ones they still require more than "new plugs and an air filter". The newer engines with their complex computer control systems require newer diagnostic tools to ensure that all the computer systems and their various sensors are functioning properly.

Timing Belts

Your 1976 or newer Volvo engine has a part known as the timing belt. This belt is what synchronizes the crankshaft and the camshaft(s). On the older 4 cylinder Volvos (except the few, rare 16 valves) if this timing belt breaks it means the engine will stop running at that very moment the belt breaks. Once you get towed in and the belt is replaced you are ready to go again. On the newer front wheel drive models and the 1992 or newer 960 & S90 models it is a much different story! These Volvo have what are referred to as "interference" engines. What this means is that the motion tolerances of the pistons and valves are so fine that if they get out of synchronization with each other the two will hit one another causing extensive engine damage. Repairs for this type of damages start at over $3,000! So prompt attention is needed on services that include a timing belt replacement on these models. The interval for timing belt replacement varies on Volvo's different engines and year models from 30,000 miles to 105,000 miles. If you don't know when you need yours replaced you can check the owners manual or call us and we can look it up for you.

 Minor Service

q Change oil and filter using genuine parts, update sticker

q Inspect front and rear brake pads

q Check tire pressures & wear patterns

q Check for fluid leaks

q Inspect wipers & washers

 Intermediate Service

q Change oil and filter using genuine Volvo parts, update sticker

q Change oil and filter using genuine Volvo parts, update sticker

q Inspect front and rear brake pads

q Inspect engine drive belts

q Check tire pressures & wear patterns

q Check for fluid leaks

q Check antifreeze protection level

q Inspect Battery levels and cables

q Inspect wipers & washers

q Check p/s fluid - top up as needed

q Check brake fluid level - top up as needed

q Install fuel additive to clean injection system

q Check Headlights, Brake Lights, Turn Signals, & Corner Marker Lights

q Test Drive for performance, any unusual noise or vibrations or other unusual symptoms

q Reset the service light and stamp the owners records book

 

Basic checklist used during a
"Full Service" or a "Major Service"

 

During the initial test drive check:

OK Attention
q q Engine performance &drivability
q q Transmission operation
q q Brake performance
q q Handling & ride
q q Climate control operation
q q Gauges & driver controls
q q Unusual noises

Checks & adjustments in the shop:

OK Attention
q q Interior lights
q q Window operation
q q Parking brake adjustment ...
q q Door locks incl. trunk/tailgate
q q Broken or missing interior trim
q q Windshield washer operation
q q Wiper operation & condition
q q Damaged or missing exterior trim
q q Exterior lights & lenses
q q Clean antenna mast and lube
q q Shock absorber response

Check fluid levels and for leaks:

OK Attention
q q Engine oil .......
q q Transmission fluid ........
q q Power steering
q q Brake fluid .......
q q Fuel system ........
q q Differential oil (if applicable)
q q Shocks
q q Engine cooling system
q q Windshield washer reservoir

Checks under the hood and on the lift:

OK Attention
q q Fan belts or serpentine belt
q q Battery posts, clamps, &cells
q q Engine protection plate and/or air guide
q q C/V boots and steering boots
q q Engine & transmission mounts
q q Front brake pads & rotors
q q Rear brake pads & rotors
q q Driveline components
q q Tire condition & wear pattern
q q Wheel bearing adjustment &sound
q q Visually inspect for bent rims
q q Inspect all suspension components
q q Visually inspect exhaust system
q q Check and adjust tire pressure

Maintenance routines:

q Change oil, oil filter, and drain plug seal
q Add fuel system conditioner
q Replace cabin filter (where applicable)
q Lube door seals and hinges
q Reset service light and replace windshield service reminder sticker
q Stamp service book

Final road test checks:

OK Attention
q q Engine performance
q q Brake performance
q q Handling & ride
q q Gauges & controls
q ..Check time on clock and reset as needed
q ..Check for any grease marks inside & out. Clean as needed.

Other comments:

Possible extras in addition to the Full Service Checklist
that are performed on a Major Service

 Extras performed during major services:
Only checked items have been performed at this time.
Unchecked items are not required at this time.

Engine Tune Up:

q Replace fuel filter
q Replace air filter
q Replace engine coolant (if required)
q Replace spark plugs
q Clean throttle assembly (if required)
q Valve adjustment (if required)
q Check engine control settings (if required)
q Service PCV system (if required)

Other:

q Replace timing belt
q Replace timing belt tensioner (if required)
q Flush transmission
q Flush brake fluid
q Replace serpentine belt (if required)

 Used Car Pre-Purchase Evaluation Report

A used car purchase can turn out to be a joy or a curse! Find out what you what you are buying before you spend your hard earned money.

We offer a pre-purchase inspection service that can prevent you from making a big mistake, give you a strong negotiating tool, and give you the piece of mind that you know what you are buying.

This service take about 1 hour to complete. It is best to make an appointment for this check out to minimize your wait.

We provide a written report with cost estimates of any repairs or services needed. The cost for this service is $90.00

Used Car Pre-Purchase Evaluation Report

Disk Brakes 101

Volvo has had 4 wheel disc brakes for over 35 years. Now virtually every manufacturer has adopted 4 wheel disc brakes due to their reliable efficiency.   Yet many customers have little knowledge of how their disc brakes work. We hope to remedy that with the following primer on Disc Brakes.

We can divide the system into two parts, the mechanical system and the hydraulic system.

First let's look at the hydraulic parts. Here is a simplified diagram.

When you press on the brake pedal you start to move a piston inside the Master Cylinder. This function is much like depressing the plunger on asyringe. As you press down you displace brake fluid inside the master cylinder through the brake lines into the brake calipers.

The caliper wraps around the brake disc. The displaced fluid from the master cylinder begins to fill cylinders inside the caliper causing the pistons inside the caliper to be pushed out. These pistons then push the brake pads into the brake rotor or disc. Since the disc is solidly attached to the axle it rotates with the tires. If you stop the disc from turning you will stop the tires from turning

On the right (above) is an animation of this process. The brake disc is not shown in this drawing for simplification. We will come back to that later when we examine the mechanical portion of the system..

We saw the brake caliper with its hydraulic pistons before in the hydraulic system. When the hydraulic pressure, created by depressing the brake pedal, moves the pistons towards the brake pads the pads are then forced against the rotors stopping it from turning.

The pad is made up of 2 major parts, the friction material and the metal backing plate that the friction material is bonded to. The view on the right shows the pads 50% worn away and the pistons slightly extended from the calipers to compensate for the worn away friction material.

As you use your brakes the friction material is worn away. This worn material is what dirties your wheels over time. It is important to replace the pads before they wear down to the metal backing plate. Otherwise your brakes will go " metal on metal" meaning the metal backing plate has begun to rub against the metal rotor. When this happens the rotor is destroyed rapidly.

Below is a animation showing the pads wearing against the rotors.

To create directional stability while stopping the front brakes are designed to do more work than the rear brakes. Therefore you will wear out your front pads faster than your rear pads. Also your front wheels get dirtier faster than your rear wheels as a result of the faster pad wear.

When you use your brakes not only do the pads wear but so do the rotors. The rotors wear more slowly than the pads wear. As a rule most of our customers will wear out 2-3 sets of pads for every set of rotors.

Below is a diagram of a worn rotor and an animation of the rotor wearing thinner where the pad pushes against it.

Once the rotor wears below a minimum thickness the disc will no longer absorb the heat created by friction during braking and the rotors become warped. This leads to vibrations while braking, felt in the steering wheel if the front discs are warped and through the body of the car if it is the rear discs. The more warped the rotors become the more violent the vibration is.

The vibration from the warped rotor is not perceptible until the brake pedal is depressed forcing the pistons and pads outwards against the rotor. With no pressure on the brakes the pistons and pads follow the rotor by shifting from side to side as the warped part of the disc rotates through the caliper. The fluid behind one piston is pushed backwards by the warp (along with the piston and pad) and the fluid behind them flows to the piston in the opposite side of the caliper pushing that piston and pad outwards. The brakes in effect float back and forth with the warp.

Below are diagrams showing the warped disc with the warped portion of the disc at the top of its rotation (left) and with the warped portion of the disc passing through the caliper (right). Below that is an animation from the hydraulic portion again showing the fluid moving back & forth behind the piston and pads (left) and an animation of the pads, caliper, and rotor (right).

The vibration from the warped disc will show up more when the brakes are applied. This is because the pistons behind each pad are now rigidly extended because of the hydraulic pressure generated in the master cylinder. They can no longer slide back in forth inside the caliper. As a result the caliper itself must now try to take up the motion.

In the rear brakes this bracket is attached to the rear suspension which is incapable of moving back and forth to the left and right as the front wheels do. In this case the caliper cannot move. Instead the disc slows even faster as the warp goes through the caliper because it has to squeeze past the pad now. This tends to be felt throughout the car. As you roll almost to a stop the last few revolutions of the rear wheels can be felt as a pulse in the stopping motion of the car as the warp tries to force past the caliper.

In some cases the warp is very slight and is not noticeable when the pads a worn down and the pistons from the caliper are extended out of the caliper. But when new pads are put in the pistons are forced all the way back into the caliper. Now the slight warp, which had previously been dampened by the pistons can no longer be dampened and the caliper is once again forced to take up the vibration. Since the entire caliper and its attaching bracket are rigidly fastened to your car the once unnoticeable vibration is felt distinctly. The only cure is to replace the rotors as well as the pads.

Below is a diagram showing the caliper bracket (left) and an animation showing how the entire caliper and bracket are forced to move left and right as the warp passes through the caliper (right).

The calipers of the front brakes are attached by a bracket to your steering assembly. When the caliper begins the back and forth motion the vibration is passed through the caliper bracket into the steering system and shakes the steering wheel back and forth while you apply the brakes.

Automotive A/C Systems

Air conditioning systems keep us comfortable during hot weather.  Everyone knows this, but beyond that level of knowledge most people enter a realm of little understood, half-magical mystery.  This is true not only for customers but some mechanics as well.

Fortunately our mechanics have all been trained in theory.  That makes it easy for our techs to diagnose problems right the first time.  The know the "how and why" each part does it's job and what happens when they don't do their job.  Most mechanics just know if they change this or that part, it fixes the problem most times (but not always).  They just shoot for the highest odds by replacing what they guess is the problem might be.

Let's take at look at cooling theory and de-mystify some of it.  You can skip some of the theory and jump to the section on why it does not cool by clicking here.  First we will  start to eliminate some common misconceptions.  Freon is not a chemical that cools things down.  Freon is a medium of transfer for heat just like a bus can be a medium of transport for people.

In fact, even the word Freon is a misnomer.  Freon is a brand name for a single refrigerant product.  Just like most facial tissue is called Kleenex, most refrigerants are called Freon. However, in both cases, Freon and Kleenex are brand names for a unique product but there are other brands of similar products that do the same job.  There are a number of different possible refrigerant products that can be used for cooling.  Whether you are cooling cars, or houses, or freezers, the application determines which refrigerant will do the best job.

Cooling is created by a process of heat exchange. Another misconception is that objects can absorb cold.  However, temperature differences only travel in one direction.  Objects can only give up their heat to something cooler. Heat always travels away from something warm towards something cooler.  An iced drink is cool because the heat in the beverage is being soaked up by the colder ice. Meat put in the freezer does not absorb cold, instead it gets the heat sucked out of it by the colder air inside the freezer.  This is a law of physics that needs to be taken as a given for this lesson.  There will be some more laws that we will also need to accept as givens which we will come to later.

As we said before, refrigerants are a medium of transfer for heat just like a bus is a medium of transport for people.  The refrigerant in an A/C system circulates inside a closed loop, going from inside the passenger compartment of the car to the front of the car, outside near the radiator, and then back inside the car. 

In automotive systems there are two refrigerants used.  One refrigerant, called  R-12, developed by Dupont was sold under the brand name Freon.  This was used in older model cars. A newer, less polluting refrigerant called R-134a is used in newer cars.  It is against the law to produce cars using the older R-12 because it was one of the primary culprits in the erosion of the ozone layer in the upper atmosphere.  Many people choose to have their older systems converted to the newer R-134a refrigerant because the dwindling supplies of R-12 are becoming more and more scarce and as a result more and more expensive.

In both cases the refrigerant is colorless and essentially odorless and exists in a gaseous state at room temperature, under the normal atmospheric pressure found at sea level.

Mixed with the refrigerant is oil to lubricate the compressor and in some cases a part called the expansion valve.  The oil circulates throughout the inside of all the components along with the refrigerant.  Sometimes dye is added to the lubricating oil to facilitate finding small, slow leaks in the system.   When refrigerant leaks out, so does the dye. With the help of special goggles and ultra-violet light the stain from the dye can help  pinpoint the leak if the car is examined within a very short period of time after the A/C has stopped cooling .   Otherwise the dye gets washed away by rain or carwashes.

Pressure on the refrigerant plays an essential role in how A/C systems work.  Here are some more laws of physics that we must accept for our lesson.  First, the higher the pressure is on a liquid the higher the boiling point will be and conversely, the lower the pressure, the lower the boiling point.  Similar to the boiling point is the condensation point.  Boiling happens when the temperature rises past a critical point and condensation happens when the temperature drops below this same point. We will refer to this as the boiling/condensation point.  When a liquid boils into a gas it is absorbing heat.  When a gas condenses back to liquid it is giving up heat.

Given that if you raise the pressure on a liquid you raise its boiling point, let’s take at look at how it effects water.  At sea level water boils at 212 degrees Fahrenheit.  Liquid water will never become hotter than 212 degrees.  Even if it is on a 500 degree fire the hottest the liquid water can become is 212 degrees.  After that it turns to steam.  The steam will  be 500 degrees or however hot your fire is!  However, if we can raise the pressure on the water we can raise its temperature by raising the boiling point.  This is the basis of how a pressure cooker works.  By raising the pressure in the pot we can heat the water up to 300-400 degrees before it boils, thereby cooking the food faster than if the water could only be kept at 212 degrees before it boils and evaporates away.

Another of our givens is that when you compress anything it gets hotter. This principal is what causes diesel fuel to ignite without a spark plug. Conversely, when you de-compress something it cools.  When you hold a spray can, while painting the can cools in your hand due to the drop in pressure in the can as the paint disperses.

A key component in an A/C system is the compressor.  It squeezes (or compresses) the refrigerant raising its pressure, it’s temperature, and it’s boiling/condensation point. It also acts as a pump to circulate the refrigerant and lubricating oil around our closed loop.

Refrigerants exist in one of four states in an A/C system while the A/C compressor is cycled on. These are, in order starting from the outlet side of the compressor, hot high pressure gas, warm high pressure liquid, then after a part called the Expansion Valve (or orifice tube in some cars) it is a cold low pressure liquid, and then a cool low pressure gas.  The state of the refrigerant, whether it is liquid versus gas, is controlled by pressure which in turn controls its  boiling/condensation point.  When the compressor is cycled off the pressure differences slowly equalize so that there is one pressure throughout the entire loop.  In this state the refrigerant is a gas and its temperature is the same as the ambient temperature wherever you car is sitting.

A/C systems are split into to halves referred to as the " high side" and the " low side" while the compressor is cycled on.  The "high" and "low" indicate the pressure of the refrigerant in each  half of the system.  The split between the two halves is bounded by the compressor (#1)  at the start  of the "high side" and at the other end by the Expansion Valve (or in some cases an Orifice Tube) at the other end of  the "high side" (#12).   See the red areas in the diagram below.  The darker the red, the higher the temperature of the refrigerant. The expansion valve or the orifice tube (whichever is used) are both are  essentially a restriction point that only releases a small amount of refrigerant at a time.  After we pass through the expansion valve and all the way back to the compressor we are in what is called the “low side”.   See the blue areas in the drawing below.  The darker the blue, the lower the temperature of the refrigerant.

Now we introduce another given law, temperature  dictates the "state" of any element. When the temperature is low enough the element involved freezes.  When it becomes hotter it melts to liquid and then when it becomes even hotter it boils.  (We never enter the state of frozen refrigerant in our A/C system so we can ignore the frozen state.)   Heat exchange is the greatest where the refrigerant changes state from liquid to gas or gas to liquid.  When the refrigerant  boils into gas it is absorbing heat.  The temperature of the boiling point (again, dictated by pressure) determines the temperature to which the refrigerant can cool.  When the refrigerant  condenses back to liquid it is giving up heat.

The temperature inside the car is controlled by setting the  point where the compressor cycles on and off.  As the temperature inside the car rises the compressor cycles on until the car cools enough for the compressor to cycle back off.  Remember the compressor's job is to raise the pressure on the refrigerant in some parts of the system and lower it in others which effects the refrigerant's temperature and boiling/condensation point. 

So lets put all this theory together and see how the whole picture works.

Like any circle there is no real start or end so we will arbitrarily begin at the end of the “high side" and the start of the “low side” which happens at the expansion valve (#12).   As the refrigerant slowly passes through this restriction its pressure drops.  When the pressure drops remember the temperature and the boiling/condensation point also drop.  This restriction in our loop is just before the "Evaporator" (#14) which is inside the car's passenger compartment. 

The refrigerant entering the Evaporator is cold, low pressure liquid (dark blue in the drawing).  The refrigerant at this point will boil at about 32 degrees if the systems operating pressures are correct.  The air in the car is 80-120 degrees.  This warm air intersects the cold refrigerant at the component called the Evaporator (#14).  The Evaporator is very similar to a radiator in look and design.  The warm cabin air is blown through the evaporator by the fan (#18) inside the car this is where the heat is drawn out of the air by the cold liquid refrigerant inside the evaporator, leaving behind air that has lost its heat.  The heat from the air  warms the cold liquid refrigerant to the point that it begins to boil and evaporate inside this component, thus giving it the name, an Evaporator.  Remember evaporation carries away heat by boiling.

We now have a cool or slightly warm low pressure gaseous refrigerant (light blue in the drawing) that is being drawn around the loop by the compressor.  Remember the compressor also acts as a pump.  As the refrigerant is being sucked in by the compressor the entire half of the system, beginning at the expansion valve, is under low pressure (blue in the drawing).  As this cool, low pressure gas (approximately 65-75 degrees) reaches the compressor it is squeezed into much higher pressure, hotter gas, maybe 150 degrees higher than it was when it entered the compressor.   Remember when we compress something it raises its temperature and its boiling/condensation point   This higher temperature, higher pressure gas is dark red in the drawing.

When the refrigerant leaves the compressor it is a very hot high pressure gas, having absorbed heat from inside the car and from being compressed.  This hot, high pressure refrigerant has a high condensation point because of the rise in pressure from the compressor.  This hot, high pressure gas refrigerant continues around the loop to the condenser (#8) which is located near the radiator in most cars.  This condenser has warm (85-105 degrees outside air passing through the outside of it.  The refrigerant inside the condenser, having been heated twice is hotter than the outside air, so the outside air now sucks the heat out of the hot, high pressure refrigerant causing it to cool.  In fact it cools it enough that the refrigerant condenses back into a warm liquid (maybe 100-120 degrees) still under high pressure.

This warm high pressure liquid refrigerant continues to be pumped around the loop until it reaches the expansion valve once again.  Here it starts the process over as the warm high pressure liquid drops in pressure (and boiling/condensation point) into cold liquid, low pressure refrigerant once again.

Why doesn't it cool?

There are a few more components in the A/C system we haven't mentioned that have ancillary  jobs.  The most important one the receiver/drier or also called the accumulator (#10).  It has 2 jobs.  One, it is a filter to catch any debris floating through the system so it does not clog the expansion valve/orifice tube.  The second job is to absorb moisture out of the refrigerant using a desiccant.  A desiccant is in essence a chemical sponge that absorbs water.  However, unlike a sponge it can't be wrung dry once it becomes saturated.  It is important to prevent any water from circulating with the freon for several reasons.  One, is that water and freon under pressure creates an acid which can erode your A/C system components from the inside over time. Another duty it performs is that if there is enough water in the system it will turn to ice when it drops in pressure and temperature as it passes through the expansion valve/orifice tube and thereby blocks the flow of the refrigerant.  The common symptom of this condition is the complaint "My A/C cools at first and then stops until I shut it off for 10 minutes".  Another complaint of a symptom can be "My A/C cools when the outside temperature is moderate but quits when it really get hot".  The desiccant can only hold so much moisture and the hotter it gets the less it can hold.  So if it is near saturation, during the mild part of the day it traps all the moisture, but as it get hotter it releases some of it which then turns into the afore-mentioned ice clog.

It is always important to replace this component any time the system has been open to the atmosphere for more than 10-15 minutes otherwise the desiccant will be saturated before you can even do anything to the system.

I just had it fixed and it has stopped working again!

Another set of items in the diagram that you see repeated throughout the system are seals and o-rings (shown in green).  Failure of any single one of these can cause the refrigerant to leak out. These seals can't be inspected unless the system is discharged (emptied of refrigerant) and then disassembled.  The clue that one has failed is there is usually an oil or dye stain around the seal or o-ring that has failed.  If one seal is replaced and the system recharged with refrigerant another one may unfortunately fail the very next day causing the same symptoms, loss of refrigerant and no cooling.

More on what can go wrong...

Connecting all the various components are pipes and hoses (#'s 5,7,11,13, & 15 in the drawing).  Sometimes a weakness in these can be seen from the outside.  It will look like a bubble on the side of a hose and is just like an aneurysm.  If caught before it breaks a failure will be prevented but the repair will be the same before or after it bursts.  Replace the affected part, any related seals, the drier/accumulator, and recharge the system.  Unfortunately many of these failures are not evident until they occur because the weakness starts from the inside and works its way outwards.

Of course, failure of any one component throughout the system ALWAYS creates the same symptom for the driver.  "My A/C doesn't work again! &%#$@!"

Another problem with A/C systems is proper charge (or load) of refrigerant.  The more you add the higher the overall pressures become inside the system.  If you read through the technical part of this article you know that pressure dictates boiling point and that, in turn, dictates the maximum cooling point.  Too little refrigerant is as bad as too much.  Just like in Goldilocks it must be "just right".

The newest systems are so pressure sensitive that the only way you can be sure of the right charge for the system is to start at a known point (empty) and recharge with an exact amount of measured refrigerant.

There is no way to cover all the possible failures for a system but this should give you some idea of the complexity.  We will be more than happy to help you understand what might be wrong with your particular case.  We will, as always, give you an estimate before making any repairs.

New and Used Parts

We maintain a huge selection of maintenance and repair parts in stock at all times.

Additionally we have a wide selection of used VOLVO parts at our Marietta location. Used parts can save money while still providing excellent service.

Our used parts are sold for 1/2 or less of retail prices!

Call any of our stores for new parts and our Marietta store for used parts.

Marietta 770-509-7900 --- Alpharetta 770-442-9451 --- Midtown 404-875-3900

 

The ones behind the scenes:

Clarke Otten – CEO Debbie Kubis – CFO Floyd Milsap - Supply Mngr.

Clarke Otten founded Professional Repair in 1985 after working 8 years as the Senior Technical Training Instructor for Volvo of North America. Prior to that he worked in different capacities at several different Volvo dealerships over a six year period. This work included being a Porter, a Technician, a Service Writer, Service Manager, Service and Parts Manager, and in New and Used Car Sales.

He is an avid travel photographer and has visited 59 countries (as of 2006) and all 7 continents.   You can see some of his photography work here:     Photos.

 

Debbie Kubis started with Professional Repair as a part time bookkeeper in 1991.  She quickly rose to CFO of the company and now is second-in-command to the owner.

Professional Repair could not have become what it is today without her valuable contributions!