Engine bay, any ideas?

[Spadey1]

I have hopefully managed to attach a picture of the engine bay on my 987 s (for some reason upside down) I opened it up yesterday to change the air filter and, aside from noticing the amount of dust (holy moly!), I spotted the wet areas on the coupling on the tube at the back. The pipe seems to link the two intakes but I believe is not the plenum (that being the pipe in the foreground). It is not too wet and I couldn’t see anything dripping but the inter jubilee clips could be tightened whereas the outer clips (dusty side) were tight and couldn’t be tightened more.

I would be interested to know what the pipe does, what the cause of the damp could be and whether it could be as simple as tightening the inter clips more (I didn’t want to over tighten in case it crushed something).

Performance seems fine, there’s no smell of petrol and nothing exciting happened when I fired the engine with the cover off. I guess it’s not impossible that a tech has sprayed it with something in the past (FSH) but if so I would expect to see more on other parts.

Any thoughts gratefully received!

Edited by Spadey1 on Monday 15th June 22:41

Edited by Spadey1 on Monday 15th June 22:42

[2Btoo]

Those two big pipes that run across the top of the engine are part of the intake manifolds and join the two sides of the engine together.

A bit of oil on them is probably nothing to worry about. It could be a failing AOS (air oil separator) but it may not be. Frankly, if it's running as it should then I'd put the engine cover back on and not think about it too much!

[Spadey1]

Cheers. I thought about the ASOS but that seems to be connected to the “dry” pipe. As you say, I’m not worried as it’s working fine, not losing fluids etc but curious as to what the moisture could be. Cover and carpets went back on a lot quicker and easier than they came off!

[LennyM1984]

For what it is worth, mine looks exactly the same (one pipe slightly wet) and (touch wood) I have no obvious issues with the car.

[Krikkit]

Definitely looks like a slight misting of oil from the way the crap's collecting in it.

I'd clean it up and just keep an eye on it, not the end of the world though, and certainly not enough oil to worry about it running low.

[Spadey1]

Thanks for the replies. If I get a dry day over the weekend I will have a go at cleaning it up and check it in a couple of weeks.

[LarJammer]

Tightening the jubilee clips can often help but as others have said, it's not a big issue. They all do it to some degree.

[A1VDY]

AOS is the problem. Take off the oil filler cap with the engine running and just try and rest it back in place. If the crankcase pressure is high enough the cap won't stay put. This points to the AOS diaphragm splitting..

[Spadey1]

I started the engine and took the cap off. There was a little resistance and I could definitely feel it being gently sucked back on to the filler but it seemed pretty mild to be honest. Revs rose slightly each time I listed it but I suppose you would expect that?