HELP! My VW '02 V6 4motion Passat sounds like a diesel, but it's not!

My car currently has about 107,000 miles. I’ve changed the oil regularly and keep it running in pretty good shape. Aside from the standard electrical problems, this car is fantastic.

Lately, however, the engine has started to sound like a diesel - it runs pretty well, but i’m concerned that this could be a bigger problem in the future. It sounds like it’s coming from the passenger side of the engine. A mechanic I recently took my car to suggested it was the valves, but assured me the engine was still okay and would last for a while…

I don’t know what to believe - i’m hearing the noise in my engine, or what I’m hearing from the mechanic! Help!

The noise you’re hearing might be coming from a worn out camshaft timing chain.

This engine uses a timing belt. But instead of turning both camshafts with the timing belt, there’s a chain between the camshafts. So one camshaft has a timing belt pulley but the other doesn’t because they’re linked by the chain.

If this chain is worn/loose, the engine can sound like a diesel engine.


It sounds like a noisy valve lifters is being cited as the cause of this noise. Most of the time this is caused by age and oil sludging/coking due to oil changes not being performed often enough.
Sometimes “regularly” is not regular enough and I would consider your car as having comparatively light use at 9 years old and with only 107k miles on it.

If this is a rattling lifter issue it should not be ignored as over time the lifter and more importantly, the cam lobe(s) can be damaged. Why the mechanic is dismissing this I have no idea.

You can try an additive to see if it will clear up. SeaFoam, Berryman B-12, etc. will work. It’s cheap and available everywhere. Just add a can to the engine oil and give it a few days to see what happens.

Thanks for the advice.

I’ve been reading about others with similar sounding problems. Many point to the cam chain or oil pump as the culprits. I’ll try the sea foam first to see if that helps alleviate the noise.

It’s been going on for a few months, and has gotten progressively louder and more concerning, which is why I was surprised to hear the mechanic dismissing it. I won’t be going back there anytime soon!

This is exactly what I had been reading about on several Passat and VW blogs.
Is this a difficult/expensive thing to repair? The camshaft chain is inside the engine casing, correct?
Is it urgent to repair this - or should I go the Sea Foam additive route and see if that resolves it?

I used the Sea Foam as ok4450 had suggested. I’m now on day three and although I’ve noticed a slight difference in the noise on initial startup, the car still sounds steadily like it did before when I drive around for a bit. I’m inclined to believe it’s the timing chain, either the tensioner or the timing chain itself that is making that noise.

What should I expect it to cost to replace the timing chain and/or tensioner if I’m going to an independent mechanic?

Did you ever find out what this was? I am noticing the same sound coming from my 2017 Tiguan. Sounds like it’s coming from the passenger side under the hood, mechanic says it’s fine… but I’m concerned.

Hi Emily, welcome to Car Talk. The person who posted the original thread has not been here since 2010, and is unlikely to see your question. I believe you would be better served by starting your own thread.

  1. Miles? 30k or 130k? Regular Oil changes? like <5k miles intervals?

my daughter is leasing a 2021 tiguan and it sounds to noisy for my likings. the first time I heard it I thought she was low on oil. its probably the noise from the fuel injectors. so It is probably normal and I wouldnt worry about it. especially if your mechanic said it was fine.