Oil cooler rebuild
 

The rebuild continues......
Decided based on some of the experiences here to pull the oil cooler out of the S8. Heads are already off so access was easy.
The only time consuming part was the Krypton Factor challenge of how to get the unit out of the engine bay once unbolted!

Oil cooler plastic pipe was in pieces, broken off at both ends. I have one of the machined pipes on order from the states so thats going in as soon as it arrives.

I set about fitting the o-ring kit last night, all sorted apart from one small o-ring approx 10mm OD. Anyone know where this fits on to

Is that for the oil filter drain plug?

That could be it! +++
Its too small for the water pipe coming from the back of the block

I'll have a look this evening and see if it is