Hello all, I have a noise near the turbo area, it sounds like an air leak of some sort. It sounds kind of like a lawnmower. It actually sounds a bit like an engine knock, but I know it isn't. It isn't there all the time, if you rev it up over 2000 rpm's, it goes away. It is definitely not an exhaust leak. Is there a problem with turbo bearings on these things? It has 88K on it. Could it be an air duct/ emissions noise? I replaced the secondary air pump because of its bearings being worn out with a lous squeal (a completely different noise). I know its hard to diagnose without listening, but just wanted some common failures from folks who are familiar with these cars. Thanks.
Do you feel any loss of power or strange boosting? Turbos do go out on these, mostly due to improper oil pressure. Also check your diverter valve, maybe the noise is coming from there.
Hello, thanks for the reply. Yes, the thing is a dog, although it has always been since we had it at 35000 miles. How would you know if the turbo is out? No more turbo "whistle" noise? Thanks.
Boost/vac gauges are really good things to have--the 1.8T cars should have had them installed from the factory. They are very helpful in diagnosing boost issues.
Now that I think of it more, it sounds like a diesel engine when idling. I plan to get a vacuum pump this weekend to rule out the diverter valve. Thanks.
Hello, I had my head under the car for a while last night and I am just about convinced that my noise is an exhaust leak. It sounds like a cracked exhaust manifold, but I can't see anything, partly due to the heat shields and stuff in the way. My small telescoping inspection mirror also helps, but I can't see it all, has anyone had this problem? I don't see any black carbon evidence of a leak, but it actually sounds like one. The funny thing, though, it goes away once you rev it a bit? Thoughts?
The flex pipe is the most common place for an exhaust leak. And if your motor mounts have leaked (and whose haven't?), that allows the engine to move more than it should, putting extra stress on the flex pipe.
Lay down by the passenger door and listen; have a helper rev the engine. You can see a little of the flex pipe from the ground--it has a woven stainless steel braid.
when you're under there, take a piece of tissue and run it around the area to see if it is blowing out of there. It may be too slight of a leak, but worth a try.
Thanks for the replys, the leak isn't by the flex pipe, which is under the car, but right near the front of the exhaust manifold/turbo area, very frustrating not to see or be able to get my hand in there. Thanks.
Hello all, great news. My noise was a cracked plastic hose going from the secondary air pump to the metal tube going to the egr valve. Thanks for your ideas though.
There should be no pressure on the plastic hose from the SAIP unless the SAIP is running. At all other times, the combi valve (what you're calling EGR) should be closed.
It sounds like your combi valve is leaking. If so, that allows exhaust gasses to flow to the SAIP, which they shouldn't. The vapors in the exhaust gasses condense in the SAIP and then ruin the SAIP (and you know how expensive that is).
The SAIP only runs for 60 or 100 seconds (depending on engine) after a cold start, then once more for a few seconds a few minutes later. Other than those times, you should be able to disconnect the plastic hose and feel no air flow at all.
Thanks a lot guys, I will get that replaced as soon as possible too. thanks, Jeff
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