New owner dumb question - what is it?

[rainon]

Hello all,

I bought my A4 3.0 TDI Quattro last week and its great. First job was an oil change, and while I was under there I had a look around checking for anything untoward. All good except for a rather oily item on the RH side of the engine at the rear end near the clutch joint. I've been trying to work out what it is, it appears to be a side connection to an oil pipe maybe. I found a Russian video which I screen grabbed to show the item (circled in red). Can anyone identify this for me?

I'm assuming if it is leaking oil this is not normal (although it is only slight).
Pipe lower RH side.jpg

[Crasher]

That is coolant pipe cap part number 4D0 133 335 and is used to seal the heater return pipe when the supplementary diesel fulled heating system PR-9M1 is not fitted.

[rainon]

Thanks Crasher, I love forums for this level of expertise

It also explains why the pipe is much larger diameter than you would expect for oil delivery. So there must be something weeping above the plug - I've cleaned it off and will keep an eye on it.

Questions answered!

[Crasher]

Possibly cam chain cover, the cover may have been off and the surfaces inadequately prepared and/or sealed, special RTV is used.