The 2.0T FSI engine found in most 2006-2008 Volkswagen and Audi A3, A4, GTI, and Jetta’s were known for having fuel pump issues and failing cam followers. This is a known issue from VW and Audi and there is even a TSB for this particular failure.
The problem with these high pressure fuel pumps is that they are a wear item by design. There is a small piston that rides along the camshaft of the engine to mechanically generate high pressure fuel to pressurize the fuel rails. Being that these are direct injection cars the fuel is sprayed directly into the cylinder. With this design, fuel pressure at the injector needs to be quite high (in the thousands of pounds of pressure) to maintain efficient atomization from the injector.
Being that this cam follower is a wear item it needs to be checked and replaced (when needed) frequently. VW/Audi has placed a 75k mile maintenance interval on this unit from release date. Based off of our findings and working on these cars when they fail, that these pieces should be checked every 20k miles if the car is stock, and 10-15k if the car is tuned. There is a DLC coating on the surface that contacts the camshaft because it is heat and friction resistant, which allows it to act as a protectorate of the tool steel the plunger is made of. Once this coating wears through there is nothing to keep the mating surface cool or protected of both the cam shaft or the cam follower.
Below is a photo of what happens in the wear process. On the Right, is a new cam follower with the DLC (diamond like coating), the middle is the cam follower from this A3, and the left is on a car that had to have its camshaft replaced. Below is also an image that shows a cut away of the follower and how it rides along the rotational mass of the camshaft lobe. So as the engine spins faster the more pressure is generated. So this follower resides in a high heat, and high stress environment consistently. This alone is enough to disprove the 75k mile maintenance theory put forth by the VAG group.
Did we scare you? Don’t worry. Stay calm and call our service department to get yours checked and/or replaced. This part only costs $55 and requires about 1 hour of labor (labor rate @ $105 per hour)