Hobbes

I have a 97' A4 with the 12v 2.8 engine. Recently it began making some odd noises. Upon heavy acceleration, the engine makes a sort of gargling noise, for lack of a better description, instead of the smooth engine note it had for the first 4.5 years I owned it. If you make a gargling noise at the back of your throat, you would get a pretty good approximation of the sound. Then, on engine braking, I get some loud irregular knocking from the engine, almost like backfires in the headers, which don't seem good at all.

I just had my timing belt and water pump replaced by my local Audi shop, along with a 75k maintenance. I also asked them to look at the problem. I don't think they reproduced the problem since it usually doesn't show up until the engine is warm. They also pulled a service bulletin from Audi saying that it wasn't a problem and no repairs should be attempted. But they gave me a copy of the bulletin and it only actually references sounds from the tailpipe on 1996 A4's, which is not my problem.

Has anybody experienced these problems? Anybody have an idea what they are? I am taking my car back to the shop to have them look at it again, but I would like some ideas before I show up.

Thanks,
Mark

maaliish

Only started happening in last 6K.

Let me know if you find out anything.

So far I do not think it is anything to worry about, but if it gets worth, then I would worry.

My car has around 70K and its a 97 2.8QM

dbtong

i definitely have the tailpipe noise as well...sigh. i've had mechanics look into it but with no luck as to the source. 79k and still running good so...

Dead

Can you describe the conditions in which this happens?

Hobbes

No specific conditions, but general everyday driving. When I first start the car in the morning the noises either don't occur or are not as noticable. But when the engine is warm, any kind of moderately spirited acceleration will result in the "gargle" from the engine.

With regards to the knocking, when tooling along at pretty much any speed, if I let my foot off the gas entirely to let the car slow (engine braking), I get loud popping knocking from the engine bay. It seems to be coming from the exhaust mainfold, although I am not positive on that.

-Mark

Dead

by something the sound can bounce back from.

Hobbes

I had that type of problem a couple of years ago (luckily while still under warranty). The dealer replaced the catalytic converter - problem solved. Had to order the damn thing from Germany.

I noticed it when going by a jersey barrier or a tall hedge. Anything that would reflect the sound. And it was easier to hear with the windows open. If that sounds like your problem you might have cat problems. Since you have a 12v, I'm sure you're out of warranty. If I remember correctly, it was around an $1100 repair (that *was* the dealer).

-Mark

dbtong

hmmm...sounds like this might be the source of noise on my car. thanks.

Dead

in another gear and no noise.