2001 a4, 1.8

Okay, so im at about 102,000 miles. Check engine light just came on, and now im getting a knocking noise. It almost sounds like there is little to no oil in the car (but there is, i checked), being that ive heard a messed up car running on little oil before.

I just get this knocking noise when idling, and only after the car warms up. After about 1.5k rpms it goes away. I found many clips on youtube of simliar sounds, but this one is pretty much exactly it.

http://www.youtube.com/watch?v=IXBqBYk6Tms

I dont have a lot of money, so id like to try and fix this on my own. Some people are saying its the cam tensioner on the responses to the youtube videos, and some people are saying timing belts, or simply low oil pressure.

Can someone please point me in the right direction. Also, anyone happen to be in Madison WI? Please help.

Thank you all very much.

Ivan

 

Hey I've got a strange noise, but it's pretty soft from the cabin. Is yours? Kinda sounds like a helicopter in the cabin.

Check power steering. Is the fluid low? High? Dirty? Put your finger or some metal rod or something onto the pump while the sound is audible. Vibrations? I'm not sure where the pump is, somewhere at the front on the belt line. Owners manual might help you find it.

 

Easy way to check PS: turn the wheel while it makes the noise and you're stopped.

 

its not my steering fluid. that leeks sometimes, and i replace it. but i know that sound. watch the youtube clip, its a knocking sound while the car is idling

 

Yeah, thats what I had and I eventually just turned the wheel and it stopped.

 

did you have a check engine light?

 

Nope.

 

did it only happen when warmed up? i can kinda hear it when the engine first turns over after a cold start.... but than it doesnt continue. Only after it gets completely warmed up does it happen. I can let it warm up idle and it doesnt seem to do it, just after driving.

When low on power steering fluid, you hear more of a wining noise. im very familiar with that.

 

the cam chain tensioner is tensioned partly with engine oil pressure (plus a spring in it). if there isnt enough oil pressure getting to the top end it might cause some slop in the chain. they do also just wear out after a while and make the same noise. if there is a lack of oil pressure to the head the valve lifters can make lots of noise as well. people often describe a bad chain tensioner as sounding like a diesel truck idling. the easiest thing to do would be to take off the valve cover and inspect everything. you can turn the engine on while the cover is removed and pinpoint the noise pretty easily.

does the noise go away as RPMs increase? get louder? is it RPM dependent? does the noise seem to be coming from the top-rear of the engine?

 

yes, the noise does go away at like +1.5k rpms. the noise seems to be coming from the valves. but not all of them, just one. idk