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.

BMW X5 – 4.4 Engine Coolant Loss

August 5, 2011

Case Studies

Atlantic Motorcar Center

This BMW had a substantial coolant loss from the engine, in the area of what is termed the “valley pan”. Service correction of this fault requires the removal of the intake manifold system, replacement of all seals and gaskets in the center engine area. While the manifold is removed, there are a number of vacuum lines and crankcase breather hoses which will need inspection and attention.

BMW has released an update kit on some of the early engine crankcase breather systems, this is prime time to install this update. As you can see from the photos, it is also a prime time to vacuum out and clean debris from the intake manifold area.

Mini Cooper – Transmission Differential Failure

August 4, 2011

Case Studies

Atlantic Motorcar Center

This low mileage car was towed into our workshop with the concern that it would not move. Initially it seemed that the clutch may be defective, but upon further inspection we found an internal transmission problem.

It seems that Mini only presses the ring gear into the differential carrier hub, rather than bolting it in the traditional method. I suspect that the ring gear is heated, to cause it to expand, and the carrier is chilled to cause it to contract, allowing a slip fit. Fortunately we were able to repair the transaxle, saving our customer a considerable expense. While the transaxle was out, we replaced the clutch as it was quite worn. The early Mini clutches do not have a good reputation for durability.

Audi A8 Quattro – Engine Timing Belt Service

August 3, 2011

Case Studies

Atlantic Motorcar Center

There is no way around it, replacement of the engine timing belt on the late model Audi A8 is a chore, but it is something that if you do correctly once, you don’t need to worry about again for 100K miles. Over the years we’ve developed some specific protocols for timing belt service on these cars, making the procedure quite straightforward, minimizing both cost and down time of the car.

Unfortunately we’ve also corrected a number of other shops mistakes, some minor, some very major. It always cost less to have it done right the first time. So if you late model Audi is due for its timing belt, give us call, and have it done correctly, the first time. With our personal service, free loaner car program, use of factory parts, and 1 year nationwide warranty, we can make even a job like the Audi timing belt, simple.

VW Golf TDi – When Good Bio-Diesel Fuel Goes Bad

August 2, 2011

Case Studies

Atlantic Motorcar Center

Towed into our workshop for a no-start complaint, the service technician had a bit of a surprise when he opened the top of the fuel tank to check for restriction in the fuel supply. A bad batch of bio-diesel fuel really stopped this car cold in its tracks. Diesel fuel is normally a yellow to clear liquid, much like gasoline. This bio-diesel fuel, made from an animal fat material, apparently did not have the proper mix of anti-gel additives in the batch. At ambient air temps below 60 it became, for all purposes, a solid mass with the consistency of Crisco.

This problem necessitated cleaning the fuel tank and all fuel lines, replacing the fuel filter, and purging the system of all of the solidified material. We then suggested that the owner should run two or three tanks of standard diesel through the system to remove any remaining material. Fortunately no permanent damage seems to have been done, and the car is back on the road, dieseling away with nearly 200,000 miles on the odometer.

Mercedes C-Class – Air Flap Lever Fracture “Snapping” Noise

August 1, 2011

Case Studies

Atlantic Motorcar Center

Hiding in the dash of that nice C-Class is a small plastic lever, which, given time and use, may fracture, resulting in a 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.

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.

BMW Z3 M Convert – Evaporative Emission System Fault

July 31, 2011

Case Studies

Atlantic Motorcar Center

Most late model cars are equipped with a system to both capture and recover vapors from the fuel system. In the past these vapors were often vented to the atmosphere, not exactly an environmentally friendly approach. The evaporative emission recovery systems are usually reliable, but from time to time, as cars age, problems do occur. In our workshop we’ve chosen to efficiently diagnose these problems through the use of a machine that creates a low pressure smoke containing a UV dye. By the use of this system, even leaks as small as a pinhole can be located.

We’ve all seen the ubiquitous P0455 – Large Evap Leak or BMW Fault Code 251 – Minor Leakage, pop up on the diagnostic computer. Often it is a loose fuel tank cap, or a deteriorated evap hose, both common for the age and mileage of most of these cars. But how many times have you found the photos below? One of our skilled techs, in process of diagnosing the leakage in the system, noted diagnostic smoke coming from the fuel tank area. On the Z3 this is no small challenge, as the entire rear suspension must be dropped to remove the fuel tank, not an easy task. But as you can see from the photos below, our techs observations were right on! A large rodent nest was found on top of the tank, and the rodents had gnawed through the evap and fuel recovery lines.

Audi AllRoad – Camshaft Tensioner Seal Oil Leakage

July 30, 2011

Case Studies

Atlantic Motorcar Center

We saved this customer from what could be a very expensive repair, a broken timing belt. Like most cars now on the road, the Audi 2.7 and 2.8 engines use a rubber timing belt. Located in a plastic housing on the front of the engine, the timing belt keeps the valve opening in sequence with the rotation of the engine pistons. A failure of the timing will allow the valves to contact the pistons, resulting in major engine damage.

The Audi and VW 1.8, 2.7 and 2.8 liter engines also use a timing chain to drive the secondary camshafts. This chain is kept in proper tension by tensioners fed from the engine oil. Over time, many tens of thousands of miles, the seals which serve to seal the tensioners to the cylinder head start to leak, note the image below. As a rule we always replace then when serving the timing belt, but sometimes they don’t make it that far. Our goal, when doing a timing belt service, is make the work last another 100,000 miles.

The oil resulting from these seal leaks can find its way into the front engine timing cover, and onto the timing belt. The timing belt, being made of rubber, deteriorates with time and can fail without warning, resulting in catastrophic engine damage. Thankfully this was caught by one of our observant techs before failure occurred.

VW Passat TDI – Engine Damage From Incorrect Oil

July 29, 2011

Case Studies

Atlantic Motorcar Center

But why do I need to use “expensive” Synthetic oil the customer may ask. To which just one of these photos should be worth a thousand words…or a couple of thousand in engine damage. The sad thing, is that this could have been avoided, with a little care, and the proper synthetic engine oil.

This Passat has a very unique engine, one of the early VW “”Pumpe Düse” design. Developed by Volkswagen in conjunction with Bosch, Pumpe Düse means “pump injectors” (though “pump dooz” is more fun to say aloud). The electronically-controlled injectors are located at each cylinder where they create a very high pressure to better atomize and more precisely meter the fuel flow. The result is increased power, improved fuel economy and – most important for sensitive North American ears – quieter engine operation.

This car, with about 90,000 miles on the odometer, has led a hard life. See those small circular “cups” in the second row of photos? They are called “Camshaft Followers”, and open and close the engine valves when compressed by the camshaft. You’ll note that two of them have actual holes worn through on the top, this is not good. You’ll also note that the camshaft, whose lobes are supposed to have a tear dropped shape, has severe wear, and many of the lobes are now close to round! This is also not good, as the engine valves are not opening fully. But even worse, is the wear on the lobes used to drive the rocker arms, which cause the injection valves to operate. The roller arm wear surfaces are also galled and damaged, such wear should not be seen at 100, or even 200K miles in a properly lubricated engine. In addition the camshaft, cam follower and rocker arm wear, one of the very expensive “Pump Düse” injection valves has been damaged. Even the camshaft bearings, normally lasting the life of the engine, are scored from inadequate lubrication. In short, the upper engine on this car needs a complete rebuild, a very pricey proposition.

Remember, cheap oil changes are the most expensive thing you can buy for your car!

Audi AllRoad and 2000 Volvo V40 – Rodent Damage

July 28, 2011

Case Studies

Atlantic Motorcar Center

A mouse in the house, or in this case in the engine air box and under the intake manifold. A real problem in Maine, we’ve heard tales of using moth balls, dryer sheets, even pepper spray to repel the little critters. I’m not sure any of these really work, but I guess its better than traveling with some extra friends on board, worse yet, suffering wiring harness or engine damage from their “creations”. Make certain your service facility checks for this when they are caring for your car, forewarned is indeed forearmed. Or to quote that tried but true old bromide, “An ounce of prevention is worth a pound of cure.”

Volvo S70 – Defective O-Ring Seals on Oil Pump Pick Up

July 27, 2011

Case Studies

Atlantic Motorcar Center

Car presented with engine making a moderately loud tapping noise, and via OBD-II a fault code was found to be stored for the variable engine valve timing solenoid. Upon inspection the technician noted that engine oil pressure warning light wire was disconnected. We connected wire and engine oil pressure warning light came on. A check of engine oil pressure with mechanical gauge showed pressure to be very low at idle, about 5 PSI, gauge is unsteady and flutters. During extended idle the reading will nearly drop to nearly zero at times. The low and unsteady gauge reading indicates possible cavitations in oil pressure.

Volvo has a somewhat common problem of defective oil pump pick up seals. These small rubber sealing rings serve to connect the engine oil pickup, located in the oil pan, to the engine block where the actual oil pump is located. After several years and thousands miles of engine heat, these seals become hardened and allow air to enter into the oil pickup system, preventing the oil pump from drawing the proper amount of oil. Early symptoms are a oil pressure light on at idle, or an engine that sounds unusually loud, often a tapping noise, at idle.

The correction for this involves removing the engine oil pan, cleaning and inspecting the pan sump and pick up tubes. The small rubber o-ring seals are then replaced on both the oil pick up and engine oil cooler. It is important to inspect the sump, and clean any oil sludge or debris from the oil pan area. As the 850 and S/V70 series engines use a two piece crankcase, you can not easily remove the main bearing caps for inspection, nor are the rod bearings readily accessible. The best test of the engine condition after this service is to use the mechanical gage again to verify pressure readings. On the car in question the engine oil pressure went from nearly zero at idle, to 35 PSI warm, and nearly 75 PSI at speed. This pressure in indicative of a engine in good condition, not having experience any wear in the bearing surfaces. Given the exceptionally low oil pressure, it is a testament to the robust design of the Volvo engine that no damage seems to have occurred.