Oily and Smokey Dumpvalve

[drlunch]

Recently i've noticed that when the dump valve is in use, i can see in my mirror a small amount of smoke/white air coming from the engine bay (most probably from the dump valve).

The dump valve: Apexi vent to atmosphere.
The car : 1996 Rev 4 GTS.

Whilst i would expect the dump valve to vent, i don't remember seeing anything visible in the last year i've had it. I inspected the engine and noticed the dump valve and the area around it is quite oily. Please see attached photos (the dump valve was oilier before i gave it a quick wipe).

Can anybody suggest why this is happening and what i can do to fix it. Performance wise the car has been fine until today when the car was on full boost and holding back drastically.

[Nick Bryant]

sounds like it could be oil seals in the turbo

[karammander]

it could be ur turbo oil seals. so when u dump it released the oil throught that. do u still have the cam cover breather still on the intake? i would take that off to a catch tank and see if it still happens or i would definatly say its turbo related.

cheers karam

[drlunch]

Thanks for answering guys. So if it is oil seals in the turbo, do i actually have to remove the turbo from the car to inspect it and diagnose this?

Karam, when you say "cam cover breather still on the intake", could you elaborate a bit more as i'm not familiar with that?

Thanks,
Tim.

[Ian Geary]

you can test for play in the turbo shaft by removing the turbo air intake and seeing how much the impeller wheel waggles.

This method isn't really scientific though - you really need to get the turbo removed and send it to some specialists, who will diagnose trouble for a small fee (£40ish).

Cam cover breather:

looking at the cam cover, there's a short rubber hose that comes out of the top into a black plastic canister (the oil catch can).

This takes oil vapour from the cam shaft area, and diverts the vapour back into the air intake system, just after the air filter but before the turbo (and dump valve).

So, if your engine is generating a lot of oil vapour (eg worn rings) there will be a lot of oil smoke being routed from the cylinder head back into your air intake, and subsequently out of your blow off valve.

By unclipping and removing this pipe when running the engine you can tell a) how much oil vapour comes out of the block and b) whether your oily BOV problem stops.

If loads of vapour comes out, and BOV problem stops, it suggests your turbo is OK and the problem lies within the engine. Next step would be a cylinder compression test etc.

If there isn't a lot of vapour (there should be a bit) then it points more to the turbo oil seals.

I've got some pics of my rev3 engine which I'll post in a bit - my BOV was spraying the engine bay with oil.

It turned out to be both a cracked piston and the turbo seals though..

Make sure your oil is topped up if the problem worsens, but the sooner you fix it the less chance there is of further damage being caused IMO.

HTH

Ian

[Ian Geary]

Here's that pic I mentioned



you can see the catch can at the bottom right, where it feeds into air filter, and see where the BOV has been spraying out oil.

HTH

Ian

[BLOODUK]

Thats alot of oil


Where does that Big pipe thats been sprayed go into , Bottom of the picture
my car doesnt have that its blocked off on the side of the pipe from the filter

Is that the catch can you was talking about?

[drlunch]

Thanks for the reply and the photos Ian. I checked the engine and the oil is definitely coming from the dump valve. By pulling the throttle cable, you can see smoke from the dump valve.

I'm pretty sure now that it's a turbo problem and from what everybody has said, i'm going to attempt to remove the turbo from the car this weekend.

[Ian Geary]

good man!

to get the turbo off I'd recommend getting some 3/8th inch drive sockets to undo the CAT heatshields and bolts.

There's sod all room around here - even after you've taken off the front engine mount and CAT stays - the 1/2 inch drive sockets just won't fit up the side of the cat!

Once you've got the CAT off the exhaust elbow, I'd remove the exhaust manifold, turbo and elbow in one go, although you can get the elbow off seperately if the bolts are playing along.

All of these bolts will be reluctant to come off - so use plenty of WD40 the day before. If it starts to undo, then gets really stiff - the bolts going to snap! Try doing it back up a bit and using more WD40, but I had to drill out most of the heatshield bolts.

Undoing the turbo oil feed is tricky as it's hidden by the turbo water feed. Again a 3/8th socket with a universal joint might get it though.

HTH - there's loads of advice on here about turbo removal.

Ian

[ryan]

Here's that pic I mentioned



you can see the catch can at the bottom right, where it feeds into air filter, and see where the BOV has been spraying out oil.

HTH

Ian

That looks VERY familiar, happened when my piston cracked

[LuizeGT]

i havnt got a oil catch can on my rev1. is that bad?

[x-pack-man]

I would recomend a 3SFE transplant, no such problems with them.

[Ian Geary]

the oil catch can I pictures was rev3 onwards, so not a problem as in it's "missing" from your rev1.

The benefit of them is that oil residue is seperated out and runs back down into the block, and only the oil vapour goes back into the inlet system.

So you may wish to uprate your crankcase ventilation, through either an aftermarket catch can (do a search on here for pictures and details), or switching it from another engine model (as X-Pack-Man suggests).

Now some people don't like even the oil vapour entering the air inlet system, and choose to vent this to the atmosphere.

But unless your engine is passing a lot of oil into the inlet system and upsetting the plugs and firing, I wouldn't worry too much about the standard set up. To be honest I'm not sure how the rev1 PCV works...

Ian

[drlunch]

Here's some more news on my oily dump valve problem. Last night I drove home and the engine warning light came on, the subsequent error code was 52 - knock sensor. Today i've done a compression test. Here are the results: Cylinder 1 (70psi), all others were around 164psi. I removed the oil cap (see photo), it has some slimy gunk around it inside it. I removed the pipe to the catch can, inside here was also some gunk (see photo). The spark plug to cylinder 1 was a lot blacker then the other three (see rubbish photo, the dodgy one is on the left). I don't know which order the cylinders should be but when I say cylinder 1, I mean the one on the air filter side NOT the intercooler side if that makes sense.

So here's my latest question. Is there anything more I can do to diagnose exactly what my problem is or is this enough information. The compression test kit suggests: insufficient valve clearances, worn piston rings or cylinder bores, poor valve seating or burnt valves, leaking head gasket.

[Ian Geary]

that's a good picture of the catch can. That white gunk in there could be caused by condensation though - and not necessarily HG failure.

Cylinder nearest the air filter is no. 4 I think. Funnily enough, my car had zero compression in that cylinder when I was having my problems back in December.

It turned out to be a cracked piston ringland (the bit between the piston rings), but this is probably not what you want to here.

With the head off you can see the state of the bores, but the piston has to come out to assess the state of the rings I think.

I think you'll need advise from some of the people with more experience of turbos on here though (JJ, Fonzy perhaps) as any of the things your compression kit tester suggests could be a cause, but some are more usual on MR2s than others.

hth

Ian