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.

VW Passat Heater Core Replacement – Clogged Core – Low Heat

Case Studies

A heater core is a radiator-like device used in heating the cabin of a vehicle. Hot coolant from the vehicle’s engine is passed through a winding tube of the core. Fins attached to the core tubes serve to increase surface for heat transfer to air that is forced past them, by a fan, thereby heating the passenger compartment.

The heater core is made up of small piping that has numerous bends.Clogging of the piping may occur if the coolant system is not flushed or if the coolant is not changed regularly. If clogging occurs the heater core will not work properly. If coolant flow is restricted, heating capacity will be reduced or even lost altogether if the heater core becomes blocked. You can see from the the photos this core was fully 3/4 blocked, doesn’t make for good heat on cold Maine mornings.

Because the heater core is located under the dashboard inside of the vehicle and is enclosed in the ventilation system’s ducting, servicing it requires disassembling a large part of the dashboard, which is rather time-consuming.


Click To See Clogged Heater Core Tubes

Read More

Jaguar XJS V12 – Multiple Oil Leaks

Case Studies

Curious about what is really under the hood of the Jaguar XJS?
To begin with, 12 cylinders, leave it to the Brits to call them 1-6A and 1-6B rather than 1-12. You’ll also find a whole lot of wiring, plumbing, vacuum switches and hoses. This “bad kitty” had a number of significant engine oil leaks, ran very poorly, and just needed general attention.

One of my past techs reminded me of that “If they don’t leak oil there’s no oil in them.”
While that is close to the truth, some oil is almost normal for the older British cars, unfortunately the oil was running right onto the hot catalytic converters and burning off…a recipe for disaster! Odd thing is another shop had just “passed” the car for state inspection…they sure didn’t do this fellow any favors…much longer and he would have had a very cooked kitty.

Enjoy the before and after photos, 60K maintenance and upper engine reseal.


Read More

1998 Volvo V70 – Clogged Engine Breather/Multiple Oil Leaks

Case Studies

We’ve seen this before, this car presented with engine oil leaks from nearly every seal.
Using our special Volvo diagnostic tool, it was easy to confirm a severely clogged engine breather box. Not an easy job, but one that needed to be handled. This was not a regular service customer car, we find this type of clogging on cars which have been subjected to “quick lube” oil changes, or maintenance has not been carried out according to the factory schedule.

In the photos below, you’ll note the heavily clogged ventilation ports, both in the black breather box, and in the engine block. Such clogging is indicative of higher mileage, extended oil change intervals, or the use of a poor quality engine oil and filter. The build up of this material prevents the crankcase ventilation system from functioning correctly, and will lead to an increase in crankcase pressure, external oil leakage and/or contamination of the Electronic Throttle Module or ETM. In severe cases it can build up enough pressure to pop out engine seals, including the rear main seal. Any problem with multiple engine oil leaks, or with the ETM must first be dealt with by inspecting and serving the crankcase ventilation system.

Breather Box Port About 3/4 Clogged

Read More

2004 Audi A4 Quattro 3.0 – Clutch Failure

Case Studies

This nice Audi came in with the concern of a slipping clutch. In fact the clutch seems to have failed in a very catastrophic way, with severe damage to the flywheel and pressure plate. The damage is so extensive that it is hard to determine exactly what did cause the failure, but my suspicion is the clutch release bearing hung up on the guide tube, keeping the clutch partially depressed and allowing slippage. After extended slippage, the heat build was great enough to cause the clutch friction material to fail and break apart.

I’ve seen this type of failure on the early Porsche 924S and 944 series, which uses a similar design. Correction entailed replacement of the flywheel – it is a fluid filled, dual mass type, the complete clutch, and the hydraulic actuating cylinder. With failures of this nature, it is important to always service as a system and replace all related components. For example, a sticking actuating cylinder, which disengages the clutch, can cause a repeat of the failure.

Audi A4 Quattro Flywheel and Clutch assembly
Clutch Pressure Plate – Note Heat Scoring Audi Dual Mass Flywheel – Note Heat Damage
Clutch Friction Disc Clutch Overview, Bearing and Guide in Front
Read More

2001 Volvo XC70 – Turbocharger Lubrication Failure

Case Studies

Volvo turbos on the 2nd generation cars generally last the life of the engine, so it was unusual to see this car here with a defective turbocharger. Half the battle in repairing anything is to figure out WHY it failed, so a repeat failure can be avoided.

You’ll notice on the turbocharger below the impeller or fan which drives the unit is severely worn at the ends. This is caused by the turbo fan contacting the housing, usually because of wear in the turbo bushings or damage to the shaft. In this particular turbo the shaft is actually broken into two parts, indicating a catastrophic failure at high speed. Under full load, the turbocharger can spin at 100,000 rpm or more, so most likely this was a lubrication failure which allowed the shaft to seize and the torque causing the shaft to snap in two.

It is very important on turbocharged cars to use a high quality of oil, the vast majority of turbo failures are lubrication related, often for poor quality oil, or infrequent oil changes. I believe that was the case here, for the service tech found the oil filter cup sludged up, as if the filter had not been replaced frequently. Or if the filter was the replaced, the previous servicing shop had neglected to take the time to properly clean the filter cup. Unfortunately it is not an uncommon occurrence to even find some general repair shops who lack the special tool to remove the Volvo filter cup, and in so doing skip filter replacement during an oil change.

Fortunately the engine seems to have experienced no internal damage, and after a proper service, the engine oil pressure returned to normal. Just to be certain, a full visual inspection of the lower engine reveled no damage to bearings or other engine parts. Replacement of the turbo unit with a factory remanufactured unit, along with the proper cleaning of the oil supply and return lines solved the problem and the car was returned to service.

Failed turbo and Volvo factory replacement Defective turbo unit
Note drive fan damage at edges “Hot” housing removed, fan damage visible
Broken shaft and damaged fan Back of damaged fan, note deep scoring
Close up of damaged fan, note fan damage Inside turbo, note broken end of shaft
Read More

2006 Volvo XC70 – Handbrake Shoe Delamination Failure

Case Studies

Volvos are great cars, but like every car there are some special service points which require attention. All too often these items are overlooked by general repair shops, the old adage “Jack of all trades, master of none.” applies here. One problem on the later Volvos is delaminating of the parking brake (handbrake) shoes. The friction material is glued, rather than riveted, onto the metal structure of the parking brake shoes. After time the adhesive holding the shoe onto the metal fails. This is often manifested by a “scrapping” or rubbing noise in the rear brake area. All too often this is ignored, or dismissed as simply rust on the brake rotors, when in fact it can be a danger sign.

Rust does occur on Volvo rotors, as it does on all cars. The only way to be certain if the parking brake system is OK is to remove both rear brake rotors and visually inspect the parking brake shoes. At any sign of delaminating, the shoes must be replaced before catastrophic failure occurs. When the friction material completely disbonds from the metal plate, it frequently gets wedged between the brake rotor and the metal backing plate, doing a tremendous amount of damage. The simple replacement of parking brake shoes, while adjusting and servicing the parking brake system may cost $130-170, but in the event of a catastrophic failure and subsequent damage to the wheel spindle and backing plate, the service cost can easily exceed $1500. As a general guideline, any car over 4 years of age, or with more than 50,000 miles on the odometer, should be carefully inspected for this problem.

Read More

Mercedes CLK320 – Climate Control Link/Motor Defective

Case Studies

Hidden in the dash of that nice C-Class are a series of small plastic levers, which, given time and use, may fracture, resulting in an unusual noise from the dash area. The noise is noted as a “snapping” or “popping” sound in or near the center vents, and the customer may also have a concern about incorrect temp or air flow from the vents. The problem, a small plastic lever which operates the foot well flaps via a servo motor. In this car, we found both the broken link as well as a defective servo motor. The servo motor had a damaged internal gear, but was not on the flap link which had broken, but rather was on a air direction flap on the passenger side.

Running a diagnostic with the Mercedes SDS computer should confirm the fault, before the teardown and visual inspection. The plastic lever in question has been redesigned to be more robust, and the update kit is available from Mercedes. The service correction is quite involved, requiring removal of the center console upper panel, radio, climate control head, and lover dash with the glove box. Once the arm is located and replaced, the SDS should be used to run a “normalization” routine on the flap system.

Read More

Audi Allroad – Water Leak – ABS/ESP Brake Module Damage

Case Studies

When this Audi was serviced, the previous service shop neglected to properly clean the water drains under the hood. On many of the Audis leaves and other debris will block the drains and allow water to build up and enter the interior of the car via the cabin air intake. Water build up will overflow and enter into this opening. In this case the electronic module which control ABS brakes and ESP – traction control, was damaged by the water entry into the car. We cleared the drains, replaced and coded the ESP module, and the car was fine. It is very important to make certain that your service shop both aware of this problem and cleans these drains on an annual basis. If you do notice water on the passenger side floor, the car should be checked at once at a qualified service facility.

Read More

VW Passat – Engine Damage – Use Of Non-Synthetic Oil

Case Studies

You’ll note the severe scoring and wear on the camshaft bearing caps on the Audi/VW 1.8 liter turbo engine. Audi and VW strongly recommend, and in some cases require the use of a full synthetic engine oil in their cars. No where is this more important than in the engine which use a turbocharger. Non-synthetic, or low quality engine oils will break down under the load, carbonize, and cause internal engine damage or turbocharger failure. This is why we always suggest the use of a full synthetic engine oil in model years 1999 or new. The oil does cost more, but does not have to be replaced as frequently, and the protection offered to your
engine is priceless.

Read More

Accessibility Toolbar