"Wet" Air Pipe - Seat Leon MK1 TDi 110

[AlexG]

I am currently experiencing power issues with my 110 TDi, I have treated it with Forte Diesel treatment, and had it on a nice long 200mile run, the turbo no longer seems to cut out, but it does over rev like crazy sometimes, normally in the lower gears and going up hill!
I popped my bonnet yesterday to find it "wet" around the red circled area on the photo.
I am unsure what it was wet with (my guess would be fuel?) and hoping one of you guys can help me out and point me in the right direction on what it is and how it could be fixed.

This might sound like a really daft question but I am not a very technical person but would like to do as much of the work as possible my self rather than paying someone else, but where abouts is the turbo located, as I am considering the "Mr Muscle" treatment if the forte stuff hasnt cleared my problem.

Thsnks in advance!

 

[Muttley]

That's almost certainly oil from the crankcase PCV system - that circular device on top of the cam cover. I expect you'll find that the small hose going in to the intake pipe is split underneath. This will allow air into the inlet system, downstream of the MAF, so unmetered.

If you can locate the leak, clean it up and seal with duct tape, it will let you see if that's the problem. Otherwise a new PCV hose is needed.

There's no easy way it could be fuel: the fuel comes in at the left, into the distribution pump, then out at high pressure to each injector via the hard metal pipes you can see.

 

[AlexG]

Cheers Muttley I will check that out tomorrow.

Could this be causing the overboost problem too? or would that still be done to the sticking vanes in the turbo or the EGR? (I did give it some real hammer - in safe places - on the 200mile run to try clear out the turbo)

 

[Muttley]

I doubt that it is causing overboost, boost is regulated by the vanes and sticky vanes is the No.1 cause of it in TDI engines. The next most likely cause is a sticky EGR valve - when that oil from the PCV meets the hot sooty exhaust fed in by the EGR system, a toffee-llike paste forms which burns onto the inlet manifold and chokes it gradually, eventually reaching back to the valve itself. It should close as revs rise, and if it sticks open, exhaust pressure feeds back into the inlet and causes overboost.

You can reduce the carbon in the turbo by getting it hot. The best way I've heard is to stick it in 3rd and climb a long slow hill at 70, keeping the revs high. You need to do that for five minutes or so. It certainly worked for me in the old TDI 110.