924Board.org

[d12-Matt]

How come my engine sounds fine when it's cold, but once it gets up to operating temperature it clicks and clacks as if the valves aren't adjusted properly. It's really noisy too - if I drive by another car or a wall or something with my window open, I can hear it loud and clear. I've checked the valve clearances both cold and warm, and as far as I can tell they are correct.

One thing I noticed is that the clicking sound was even louder one time when the oil level was low. I had to add about 3/4 of a quart, and then it went back to the "normal" noise volume.

Does the type of oil I use make a difference on how the engine sounds? Is the 924 Audi engine just plain noisy or is something not right with mine?

[Mike77]

I had a wierd sound too, when mine warms up. It didn't really sound like valves tapping, but like a very fast clattering/metal brushing sound (hard to discribe). I replaced the timing belt tensioner pulley with one from my parts engine, and the problem seems to have cleared up. When the bearings start to go in that pulley, they will clatter, and a mechanic friend told me it would get worse after warm up.

[Diesel]

Mine is just the opposite, when it's cold I've got clatter like a hanful of marbles is loose in the engine. When it's warm, it's smooth as silk. Oil pressure never goes below 2 Kp/cm3, so I'm not going to worry.

[Rick MacLaren]

Uh oh....

[Rick MacLaren]

On my rebuild you can hardly hear it running, even with no catalytic converter, and so anything even remotely sounding like noise is worrysome.

The same loud sound, coming from what appeared to be the head, came from my car before it blew, but it happened at any speed.

[JvGinPDX]

Engine noise on engines with lots of miles on them is often a result of bearing clearance increasing due to wear. Thin oils will make the engine sound louder than thicker ones. I use 20-50 dino, and I get low noise and good oil pressure

[Smoothie]

Excellent point.
Does this work on people too? I noticed both knees cracking loudly when I walked upstairs yesterday. Where can I get some 50 weight olive oil?

[d12-Matt]

Hey, would you guys be able to tell what the noise is if I were to record one sound file of the engine running while it's cold and one of when it's warm and let you listen to them?

I'm using 20W-50 oil and the engine shouldn't be too worn out because the original engine was replaced with a rebuilt one in 1987.

Mike77, I don't have a spare timing belt tensioner pulley to check if that's that problem. Is it possible to just grease it to see if the noise goes away?

[Mike77]

I really don't think it's greasable, but when I took mine off and spun it, I could here a "softened" version of what I heard when I ran the engine. Like a bunch of little worn bearings spinning. It's easy to remove; maybe you can take it off and see how it feels and sounds. Just don't turn the cam pulley or crank the engine while the timing belt is off Haynes manual will show you how to retighten the belt if you have never done it.

[numbers]

Smoothie, I have found that a couple of beers works better for lubricating knees.

[Smoothie]

[Mike77]

Sorry Matt, I ran mine for a while today, and I think that sound is back so maybe it wasn't my tensioner pulley. Whatever you've got might be my problem too. Between stuff like this and the never ending hot start problem, I'm about ready to part ways with this car,which would be a shame since there are so many things about the car that are really nice.

[JvGinPDX]

To Mike 77

I replaced my timing pulley, the cost was about 35 dollars. It made a world of difference in how the car sounds. Of course I did the belt at the same time. It cost about 10 dollars. My hot start problem went away after doing the hot start fix in the Technical Section. These cars take some work because they are old ank kindof odd, but you would spend more money on an other car that is not as much fun. Good Luck

[kevrl]

Matt,

Yupp, I had this exact problem on my 931. The Cam was slightly worn, but not too bad, in any case I changed the Cam and oiler tube and plastic elbow all at the same time, and since then - no noise. I'm not sure what cured the noise, possibly it was the new oiler tube, as it was leaking around the plastic elbow. There might be enough oil pressure on a cold engine to make up for the slight crack in the oiler tube elbow, but not enough pressure when warm. - I'm guessing here. In any case the noise is GONE.

Kevin