volvopentaman

Hi!

I have a severe case of oil leak on my friends 1998 3,7L V8 (AEW engine code). The leak comes from the "leak-detection hole" below the oil pump pulley. There is a 4mm hole below the bearing carrier, and it does not leak when the engine is cold.

The weird thing is, that the leak starts after around 10minutes of engine running, not a drop before that. After the leak starts, it puts out around ½L per minute!!!

I've spent soon 20h on investigating the leak, before finding out exactly where the leak is.

I replaced the bearing carrier of the oil pump pulley, it has a built in gasket on both sides. The gaskets were totally demolished, so i thought the leak was there. I replaced the upper breather hoses between the cyl.heads and from left cyl.head to the lower-breather "tank" below the intake manifold.

I've taken off the intake from the engine too, just to make sure the problem isn't there. Underside of intake was dry as a desert.

The whole problem started when my friend had driven like 10minutes on the highway, after starting from home, when he did a kickdown overtake.

Could there be something in the oil pump causing this?

volvopentaman

Took the oil pan away, and found nothing.

Except when i checked out the parts catalog, and noticed that there should be a radial seal between the oil pump axle and the axle carrier bearing, marked nr. 16 in this picture:

Audi A8 1998

There is NOT, and was NOT a seal there, when i started taking the engine apart. The car has been at the same owner for 8 years, and only has 140.000km on the clock... weird... could the seal have been smuthered to pieces, as the seals on the pump tooth-wheel bearing carrier were...

volvopentaman

Probably solved, the radial seal behind the oil-pump bearing carrier was totally ripped off, just the outer ring left, no seal. Wonder where the seal bits have gone, because they were NOT in the olipan, oil-pump, nor in the filter or oil pump pickup "filter" in the oil-pan.

I'll post tomorrow, if it doesn't work.