I 've had smoke from the right side of the engine bay for about a year (MY05 WRX). I concluded that this was due to leaking rocker cover gasket. I've replaced this along with x2 half moon seals (took me 3 attempts to get it right) but there's still smoking appearing from the right side. The smoke is like a burning rubber smell so I'm fairly sure that it's oil. Yesterday I put my hand right down at the bottom of the rocker cover and there is no oil around here. The up pipe heat shield seems covered in oil but I spilt quite a bit when I replaced the rocker cover gasket (in fact I used 3 in 1 spray oil to 'wash' off the old gasket fragments that covered the cam lobes etc before putting cover on). I had hoped that the old oil would burn off but now 60+ miles later, it's still smoking. The plastic undertray has been left off so that I can check underneath easily.

Any advice on likely cause?

2 possibilities I think:

1. Rocker cover gasket still leaking from an area that I can't quite see.

2. Leak from turbo oil return pipe. Apparently this sits underneath the turbo so is difficult to see. I've heard that it can crack and then leak.

If it's the turbo oil return pipe what's the best way to see the leak?

Any ideas welcome.

D.

 

Sounds like crank seal to me, mines been leaking for a while now, will be getting it done when get the cambelt done. Drips onto the manifold

 

also, just a tiny drop of oil - makes a fvck of a large smoke cloud

so it may be some left over still

 

Thanks.

It might be improving with time so still not certain that there's an ongoing leak. Regarding crankshaft seal, I replaced cambelt only 2 months ago and didn't see any oil leak then.

 

Oil seperator gasket? The top of this picture.

http://www.importcarparts.co.uk/part...ey=&searchPart=

http://www.importcarparts.co.uk/part...y=&searchPart=

 

This sounds similar to what I had recently on a MY54 STI, mine was the oil line from the turbo.

Really easy to see where it leaks from



the joint half way between 1 and 2. You can see this when looking at the turbo and will look wet after a hard drive etc. might be worth a check.

 

Managed to get car up on ramp (helpful local mechanic). There's fresh oil running down from bottom of cylinder head at back of engine. This looks as if it's still leaking from lowest rear corner of rocker cover although you can't see this fully because of up pipe. One of the half moons is near by but it looks ok. I think that I will cautiously give the three bolts in that area a quarter turn. I'm aware that they have a habit of shearing but they're really not tight at the moment (manual says 5 lb ft torque which is nothing).

 

Ps already changed oil separator gasket. When I decided to replace RC gasket, I also got 2 half moons and oil separator gasket. It's dry in this area now. Def leaking from bottom.

 

Seems these rocker seals are a right pain! Mine is doing something similar but I believe mine is either crank seal or separator gasket. Did you manage to fit the separator gasket with the engine in the car?

Hopefully a little nip up should sort your problem out unless it's the oil return from the turbo. Very common leak I hear.

 

Replaced oil separator gasket when rocker cover was off engine although I think that replacing it when on engine wouldn't be too difficult.

These seals are difficult to replace mainly because there's very little clearance when putting back cover. It's very easy to snag lower part of gasket on cam cap pushing it out of the groove in the cover. I did this second time and had major oil leak on start up. The first time, I forgot to tighten top front bolt and as this part had bead of sealant under seal, the sealant set in uncompressed form. On third occasion I opted for sealant all the way round (Three bond 1215 by the way) and was ultra careful to not move rubber gasket.