Case Studies

A Collection of the Odd, Unusual and Interesting Found While Servicing Our Client Vehicles.

Originally intended as a showcase for customers of our workshop and staff’s abilities, this page has evolved in an interesting and informative teaching tool, and one of the most popular pages on our site!

By nature, these are rather extreme examples of failures, and not what we typically find during service. Our goal at Atlantic Motorcar is to prevent these from happening to you and your car. But rest assured, if we can fix these challenges, regular maintenance is breeze!

We like to call this our “YES WE CAN!” page. You can also view many of these concerns on our Facebook page. Each photo can be enlarged by clicking on it.

Audi A6 – Constant Velocity Joint (CV) Boot Cracking

July 24, 2011

Case Studies

Atlantic Motorcar Center

I should first mention that this is not an Audi problem, but is a concern on any front wheel drive vehicle, as well as some cars, Mercedes and BMW, which use CV joints on the rear axles.

Just in the nick of time, one of our techs noted the deep cracking on the constant velocity (CV) joint boots during a scheduled service of this car. The axleshaft is used to transmit force from the transmission to the wheel. The CV Joints allow the axle to pivot when the wheels are turned, and rotate at the speed of the front/rear wheels.

The CV Joints are covered with a protective rubber boot which keeps out dirt, and keeps the lubrication inside the joint. When the protective rubber boot splits or tears, this allows the lubrication to be thrown out of the joint, and dirt and debris to enter. A damaged CV Boot will lead to a rapid failure of the CV Joint itself, complete failure of the joint will prevent the car from moving. Often, but not always, a pronounced clicking noise can be heard from damaged joints. To minimize expense and CV joint replacement, these rubber boots should always be inspected each service for splits or tears, and replaced BEFORE failure occurs.

VW Jetta Diesel TDI – Dual Mass Flywheel Failure

July 23, 2011

Case Studies

Atlantic Motorcar Center

Great idea, poor implementation. Sometime back in the early 1990s Porsche tried this in the 911 series, it did not work out well then, and it seems not to have worked well now. The dual mass flywheel is composed of two parts, damaged with silicone to soften engine noise and impact shock during clutch engagement. Often, with older and high mileage cars, the silicone and damping material fail on the dual mass flywheel, resulting in engine noise, vibration, and excessive lash in the driveline when engaging the clutch. This vehicle experienced the failure at about 50K miles, really quite low as far as clutch life normally goes, but apparently quite common with the dual mass design.

The repair can be approached two different ways, taken from either a cost or durability standpoint. The costly method, and one which we feel not to be durable, is the installation of the same expensive dual mass flywheel unit, with the attendant failure problems down the road. We suggest the replacement and update of the complete clutch assembly to a solid flywheel design. The proper solid flywheel replacement has the approximately the same mass as the dual mass set up, so the exchange is all but transparent to the driver. Aside from the cost benefits, durability is of course improved with the solid design, as there is no longer any damping material to leak out, or become damaged. The photos below show the original dual mass set up, and the replacement, solid flywheel kit. Note the use of multiple discreet damping springs in the clutch disc on the solid flywheel unit, this takes the place of the damping material in the dual mass flywheel.

Audi AllRoad – Heated Steering Wheel Problem

July 22, 2011

Case Studies

Atlantic Motorcar Center

After no less than 5 trips to a local Audi dealer, and over $1,100 in repair bills, this car landed on our doorstep. Now, as a former AllRoad owner, I have soft spot in my heart for these wonderful cars, complex as they may be, so I viewed this as an enjoyable challenge! The problem, the heated steering wheel did not work. Yes, you read that right, some of the Audis do have a heated steering wheel, and as a Audi owner I can testify that its might nice to have on those cold Maine winter mornings.

On the Audi AllRoad, the steering wheel heater operates off the driver’s seat heater switch. Its actually a little more complex than that, as Audi also places the horn, Audio and Telephone control buttons on the steering wheel, as well as a locating a handy safety device, called an Airbag, there. Many of these signals run off a CAN (Controller Area Network) Bus system, to eliminate the number of wires needed. Think of the CAN Bus system much like a USB system on your home computer, a variety of different peripherals plug into a common set of wires, each addressable from the computer. Perhaps this sounds complex, but it is not easy to run a dozen or so wires to an object, the steering wheel, which is constantly rotating.

The long and short of the problem was this. Prior to the car arriving at our facility, the steering wheel had been replaced in a misguided attempt to correct a fault. After the 5 trips the dealer gave up and told the customer they did not know what was wrong with the car. Now we get stumped from time to time here, but you can be certain we never give up after charging you $1,100, we will work to a solution.

It took some time to properly diagnose, and in the case of most electronic parts, diagnostic time is always less expensive than just throwing a part at it. After removal of the radio and center console, to access the climate control unit and test the seat heater switches, our tech found the electronic “cassette” located in the steering column, to be defective. In fact, upon removal of the Airbag and steering wheel, we found a wire clearly broken away from the cassette contact, you can see this one of the photos. This is not considered a repairable fault as the Airbag safety system runs through the cassette, and the proper solution was replacement. Bottom line, its always less expensive to pay for diagnostic time than parts. Now the car is happy, and so is the customer!

Audi TT Quattro 1.8 Turbo – Defective Water Pump

July 21, 2011

Case Studies

Atlantic Motorcar Center

This car has was diagnosed with a defective engine coolant pump. Symptoms were overheating and noise from the front timing belt area. Disassembly of the front cover and timing belt, no easy task on at Audi TT, allowed for removal and inspection of the pump. As you can see from the photos, it is a bit of a process to access the pump, so be sure to always replace the timing belt and tensioner at the same time.

The timing belt, scheduled by Audi for replacement at 105K miles, has a history of failing considerably sooner, so consider timing belt service at 70 or 75,000 miles. The mode of failure with this pump appears to be a simple design flaw. The water pump impeller is made from a plastic material, the plastic becomes brittle with age and extended immersion in the hot engine coolant, and simply cracks apart. The defective pump, and pieces of the failed impeller, are on the left side of the photo, the new pump on the right. As this car is an aluminum alloy engine, Its always a good policy to flush the cooling system at least every two years, or 30,000 miles, and to use a quality antifreeze with corrosion inhibiters.

Volvo V70 GLT – Defective Turbocharger

July 20, 2011

Case Studies

Atlantic Motorcar Center

This car has was diagnosed with a defective turbocharger unit. Note the large amount of oil build up on the pressure side of the turbo, especially in comparison to the new turbo on the left. This oil is then drawn into the engine, resulting is severe smoking from the exhaust, high oil consumption, and even damage to the catalytic converter.
Note the Volvo replacement turbo box, we always use factory parts for reasons of longevity and proper fitment.

On late model car turbo failures are uncommon if the vehicle is cared for properly. Indeed, with proper care service life of 175 to 200K miles is expected. Turbo failures occur from two basic causes, lubrication failures, consisting of infrequent oil service, or incorrect grade of oil, and foreign material entering into the turbo and causing blade fracture. We strongly advise to never go more than 3-5,000 miles on conventional oil, and never more than 5-7,500 miles on a full synthetic. We recommended and use Castrol lubrication products in our workshop, either Castrol GTX, or Castrol Syntec.

Volvo S70 Turbo – Electrical Fault in Dash/Alternator Failure

July 19, 2011

Case Studies

Atlantic Motorcar Center

This car had an interesting story. The car presented with the charging light on, indicating alternator failure. The alternator light would flicker, turning on and off rapidly. Alternator failures are somewhat uncommon on the later Volvo S70s, but a charging system analysis showed that the alternator was indeed not charging under load, even when full fielded. 12 VDC was found at the field wire during the testing. We replaced the alternator with a Bosch remanufactured unit and then road tested the car. The alternator light came back on, but was steady, not flickering as before. We checked for voltage on the field wire, no voltage.

A check of the schematic showed that the field wire was powered up via the dashboard and indicator. We tried tapping on the dash and noted that the light would go out. We removed and inspected the instrument cluster, no fault found. The tech then followed the harness down under the dash and found a poor connection at a large multi-block connector. Correction of this fault corrected the charging issue and the new alternator will not fail or become quickly damaged like the former unit.

Audi S6 – Timing Belt Service w/ Water Pump

July 18, 2011

Case Studies

Atlantic Motorcar Center

The Audi S6 timing belt service does not normally require removal of the nose of the car, but in this case the silicone filled fan clutch was seized onto the idler shaft and could not be removed with the nose in place. 10 years and more recently time in the coastal environment seemed to have done its worse. To fully access the clutch required removal of the front bumper cover, radiator support and radiator, evacuate and recharge of the A/C system. As the engine water pump is driven off the camshaft belt, it is a good idea to replace the pump at the same time as belt service. All tensioner rollers should be inspected or replaced at the time of belt service.

Audi A8 – Head Gasket Service

July 17, 2011

Case Studies

Atlantic Motorcar Center

Timing belt replacement on the Audi A8 requires a fair amount of disassembly on the front end of the vehicle. The Audi 4, 6 and 8 cylinder engines are high compression types, failure of the timing belt will result in major engine damage. Although scheduled by Audi for 90,000 miles, we have found loose or severely worn timing belts and tensioners at the 75K mile mark. When replacing the rubber timing belt, all belt rollers, water pump and thermostat must be replaced. This is a service you only want to do every 100,000 miles. We have noted a number of the Audi V8s with head gasket leaks or seepage, this is a straightforward matter to correct when the car is disassembled for the timing chain.

BMW 525 – Defective Heat Exchanger (Heater Core) in Dash

July 16, 2011

Case Studies

Atlantic Motorcar Center

This car has was diagnosed with a defective heat exchanger, also know as a heater core.
The heater core as used in this BMW’s climate control has hot engine coolant flowing through it during operation. The heater core, which is comprised of a an aluminum core and nylon tank ends had developed at leak at the interface. This area is often sealed with rubber o-ring which fails after long term exposure to heat and coolant.

Once the o-ring seal fails, coolant will begin to seep out of the heater core into the heater box producing a strong burning smell from the dash vents. This can lead to long term problems if the antifreeze gets onto or into control motors, servos or air direction flaps. Like most heater cores this unit is somewhat buried in the dash, necessitating a fair amount of disassembly to remove and replace. Its always a good policy to flush the cooling system at least every two years, or 30,000 miles, and to use a quality antifreeze with corrosion inhibiters.

Mercedes 300SDL – Fault In Climate Control System

July 15, 2011

Case Studies

Atlantic Motorcar Center

Car presented with Incorrect air flow out the heat/ac vents. Upon inspection we discovered that a previous servicing facility had worked on the vehicle and left the ACC system in total disarray. Vacuum lines were disconnected, flaps were wire tied closed, actuators were disabled, vacuum manifolds were plugged, in short, the ACC air direction system was non-functional. This required removal of the dash pad and center console to fully inspect and access what was needed to make the system operational once again. Subsequently upon removal we found broken flaps, damaged cable actuators and stripped gears. This is a major undertaking, and it all has to be right before the dash is reinstalled back into the car.