Auto gearbox oil change - a8 quattro d2

[sloss]

Originally Posted by notorious

>> running idle it sounds like a diesel engine

Camshaft chain tension is maintained by oil pressure in our engines AFAIK.

If oil pressure is not that strong enough at idling, then chain starts to rattle. When RPM goes above idle, the oil pressure becomes strong enough to tension chain properly. Change oil pump and problem should disappear.

But it's a petrol engine so will be cambelt - yes?

[mannyo]

Each bank of cylinders is driven by 2 camshafts (V8 has 4 camshafts) , the first camshaft is driven by the cambelt whereas the second camshaft is driven by a chain that connects both camshafts together inside the head.

[Dezzy]

I'm guessing it's CML, it's also on the box it's self but you'll have to get it on a ramp or similar to see.

I had my box done recently, fluid and filter. No issues...... Yet!

[notorious]

Right. These two chains are located on the back side of the engine. So if engine sounds diesel when idling the first thing is to chech the sound of back top side of cylinder head, not the front side where all pulles and belts are.

If these are chains, than it's almost 100% low oil pressure at idling. Warning lamp still doesn't come on, but it is enough to hear the rattling sound. Can be further diagnosed by measuring oil pressure at idling by connecting manometer.

Subframe out, engine sump out, and check if oil pump is clogged with debris. If not, then change oil pump (plug and play operation).

[ainarssems]

Camshaft chain tension is maintained by oil pressure in our engines AFAIK.

If oil pressure is not that strong enough at idling, then chain starts to rattle. When RPM goes above idle, the oil pressure becomes strong enough to tension chain properly. Change oil pump and problem should disappear.

His is 96 32V, no chain tensioners on 32V

[notorious]

I'd better get my coat.

Din't pay attention that this is 32v car and didn't know those engines don't have tensioner.

The reason why I was so sure is because I know car which has exactly the same problem with diesel sound when idling and it was fixed with oil pump change. It was 5v per cylinder engine though.

Thanks for pointing out