Piston Slap: The Golden Ticket to the Sludge Factory

Chris writes:

Hi, Sajeev. I’ve got a Piston Slap question for you. I have a 2003 Jetta with a 1.8 L turbo engine. Recently, the water pump failed (at about 68k miles). My imminently competent and trustworthy local independent garage replaced the water pump and told me that they heard a tapping sound coming from the engine. They changed the oil and the sound seems to have gone away, but I was advised by them to trade the car in right away if the sound comes back. Do you have any intelligence on 1.8T VW’s and what their longevity is after overheating?

Sajeev answers:

Thanks to the Internet we all know about the 1.8T’s mad sludging skills. And what you said about your Jetta isn’t exactly confidence inspiring.

Regarding longevity: there are too many variables to say for sure. For example, how long the motor overheated, did coolant leak into the oiling system, the quality and frequency of oil changes, condition of the PCV system and your driving style all play an important role.

And if you’ve (no offense) been bad about oil changes, you’re asking for a sludge problem. After all, this is a small displacement, turbocharged engine with a marginal oiling system that’s pulling a 3300lb Jetta. Luckily, your car is eligible for VW’s engine sludge recall, so talk to your mechanic to see if the work needed (or will need) falls under the warranty:

“After listening to you, our valued customers, Volkswagen is implementing an extended warranty for oil sludge related repairs for 1998–2004 model year Volkswagen Passat equipped with the 1.8L Turbo engines to 8 years from the vehicle’s original in-service date without a mileage limitation. This extended warranty is fully transferable to any subsequent owner. This extended warranty does not affect—and is in addition to—any other applicable warranty covering your vehicle.”

Valued customers, indeed. So good luck with your quandary.

[email your technical queries to mehta@ttac.com]