[Jesse N.]

I'm really pulling my hair out here. I put my car away last fall and everything was fine. I changed so turbo related parts and built new headers over the winter. I finally got it all back together and now its leaving a smoke trail from the pass side bank. Under power there is no smoke but it leaves a pretty good fog at light throttle. I've pulled the turbo off that side and there is no signs of leakage. Plugs looked pretty good but #4 had a little oil on it. Ran a compression check all at 150 but 2 and 4 are 140-145. I resealed all the intake rocker studs and eliminated the pcv valve with no luck. Also there is very little blow-by.

I looks like there is oil in the intake plenum but I can't tell where its coming from. I pulled the intake and on the surface of the head below the port for #s 2 and 4 has a little oil on it. The rest don't seem to have that. I'm hoping it is the intake gaskest leaking but they really didn't look that bad. I guess I'll find out tomorrow.

Anyone have any other ideas? If the intakes not it I'm gunna freak. I'm supposed to go racing this weekend but now its not looking good.

 

[jbird]

I guess the intake would make sense if it is smoking at light throttle, but not under boost. Do turbo engines have vacuum at light throttle? If so that might explain it.

 

[Jesse N.]

Yea is got a real sissy cam in it. It will make 14'' at idle and 20'' at cruise.

 

[jbird]

Yea is got a real sissy cam in it. It will make 14'' at idle and 20'' at cruise.

Sounds pretty likely it's the intake gasket, since both vacuum and smoke go away at WOT.

 

[rustbucket79]

Get the intake surfaced before reinstallation, to guarantee 100% clamping force on the gasket. I like to use the Mr Gasket intake gaskets for boosted applications, #121 I think. I also silicone both sides around the intake ports, install the intake but just finger tighten the bolts, let the silicone set for an hour, then torque to spec.

 

[novaderrik]

check the oil seal in the turbo housing itself.
can't hurt..

 

[godsend]

Looks like a seal problem in your turbo.

With woth youll get pressure on compressor/turbine housing. But at cruise it can suck out oil.

 

[Jesse N.]

I pulled the turbo apart and there is no sign of oil on either side. When I put the intake back on I'm going to switch the turbos side to side to see if the problem moves.

 

[turbodave]

Jesse, you probably have a drainage problem on the pass side. Not uncommon. The crank throws all the oil and windage at the pass side of the the pan. Probably the easiest thing you could to right now would be to use a larger oil drain on that side. I always recommend at least a -10, but a -12 is preferred. If you took the housings off and both sides are dry, then the oil coming out of the motor, not the turbo. Call me later if you want 1-800-297-3626.
We have at least 600-700 S400's out there and I have yet to see one with a seal problem.

Dave

 

[stock48]

Jesse, you probably have a drainage problem on the pass side. Not uncommon. The crank throws all the oil and windage at the pass side of the the pan. Probably the easiest thing you could to right now would be to use a larger oil drain on that side. I always recommend at least a -10, but a -12 is preferred. If you took the housings off and both sides are dry, then the oil coming out of the motor, not the turbo. Call me later if you want 1-800-297-3626.
We have at least 600-700 S400's out there and I have yet to see one with a seal problem.

Dave

That's what I was thinking. Sounds like it oil could be backing up in the drain back to the pan. Also super high oil PSI, or too thick of an oil can cause smoke with a turbo.

 

[Jesse N.]

I have a -10 drain off each turbo and the fitting into the pan is in the kickout behind the windage tray. There seems to be alot of oil in the intake manifold so I'm going to replace all the valve seals on that side and try it again. Hopefully that will take care of it. I really don't think the turbos are causing the issue. Thanks for all the replies.

 

[Jesse N.]

Well, I think I found it.

On the right bank there was three exhaust valve seals popped off the guides. I got some better replacements and got them put in but its a little too late for racing this weekend. I've got to get it in for an alignment first and I won't have it back together in time. I guess I'll just have to wait.

 

[Jesse N.]

Ok, Still beating my head against the wall.

I replaced all of the valve stem seals. Turns out there were just as many popped off the drivers side and no smoke from that side so guess what... I still smokes. I decided to pull the head. I found about two tablespoons of oil sitting on top of the intake valve on #4. Judging by the exhaust ports #4 has the issue and cylinders 2 and 6 are catching the overflow. I also found that it pushed the head gasket between 2 and 4 explaining the slightly lower compression in those two compared to the rest. The head is at the machinist to get resurfaced and checked out. The trouble is we can't find anything wrong. The valve guides look tight to both the valve and the head. Can't see and cracks or any other issues.

What I can't explain is the volume of oil on that intake valve. It must be draining there after is shut off because it would smoke all the time and probably empty the pan in a couple of minutes if it pulled in that much oil with each revolution. But where could it come from?

I did replace the intake gaskets too. I can't say for sure thats not the problem but the engine ran almost two years without a problem with these same gaskets.

Any more ideas???