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TD04 turbo smoking

Posted: Mon Aug 08, 2016 4:20 pm
by Pielikey
Hello, (I also posted this to

I picked up a 91 legacy SS with a TD04 waay back in January and am just now putting back together all the pieces to get it roadworthy, safe and legal. Unfortunately smoke pouring out of the hood scoop does not make for a very legal vehicle.

It seems that the car idles okay & drives around under vaccum just fine, but when the car goes under boost, the turbo itself starts to smoke, as well as under the uppipe's heat shield, as if oil was running down the uppipe. It then continues to smoke for awhile afterwards. It smells similar to burning oil. Here's what I've checked so far:
-power steering lines are not leaking onto the uppipe
-oil drain line is not leaking
-I replaced the banjo bolt gaskets for the oil feed & coolant lines
-CV boot is not flinging crud onto the downpipe (was worth a shot..)
-Right side valve cover gasket is not leaking onto headers

This is also not happening on a very high amount of boost. I'm running wastegate pressure which is about 5 PSI.

I'm also not sure how old the TD04 is, but judging by how old the exhaust gaskets were, I would say it's been on the car quite a while.

If anybody has anything else I can check or any other advice on this issue, it would be appreciated! All I can think of that is left is the seals on the turbo itself, which means rebuilding the turbo or replacing it.


Re: TD04 turbo smoking

Posted: Mon Aug 08, 2016 5:15 pm
by Legacy777
Welcome to the BBS.

You may have an oil seal in the turbo that is going or gone. Does it smoke at all out the exhaust?

Does it sound like you have an exhaust leak at all?

The first thing I'd suggest is trying to determine whether the smoke is coming from inside the turbo through an exhaust leak or if it's caused by oil burning off the exterior of the turbo. I'd suggest removing the turbo chimney to get a better look at the turbo.

Re: TD04 turbo smoking

Posted: Mon Aug 08, 2016 5:29 pm
by Pielikey
Thank you for the quick response.

It doesn't seem to be smoking out the tailpipe (other than exhaust gas), and it doesn't sound like an exhaust leak at all. When I shut the car off it can continue to smoke for a few minutes. Looking at the turbo it seems like the smoke is coming from the turbo itself (possibly underneath it?). I'm pretty sure it's oil (it kind of smells like it) leaking onto the turbo or exhaust from somewhere.

Re: TD04 turbo smoking

Posted: Mon Aug 08, 2016 5:33 pm
by Legacy777
You may want to take the car to a car wash place, spray engine degreaser on the engine, and then pressure wash the engine to try and remove some of the oil so you can see where the oil leaks are coming from.

If you have any exposed wiring or other electronics that may be susceptible to water you should fix or protect them before spraying high pressure water at the engine.

Re: TD04 turbo smoking

Posted: Wed Aug 10, 2016 5:04 am
by seltzer
Exact same thing is happening to my 94 Legacy SS. Pielikey- Curious to know if you've found the source. I'm debating rebuilding the turbo or trying to get another on in there.

Re: TD04 turbo smoking

Posted: Wed Aug 10, 2016 10:10 pm
by Pielikey
What I tried doing was when I took the turbo off before to put some hose clamps on the oil return line (there weren't any before and I thought that had fixed the issue - not so, apparently) was I used some degreaser to scrub off some of the crud from the engine bay around that area. having taken the turbo off a second time now, I didn't find anything enlightening - It's almost as if there's oil dripping directly onto the uppipe. I'll take the heat shielding off tomorrow and look to see if there's any oil on the uppipe, but I have a feeling most of it will have been burned off...

What I'm doing for now is I'm going to be replacing the turbo with a decent used TD04.

Re: TD04 turbo smoking

Posted: Sat Aug 20, 2016 7:06 pm
by Pielikey
Just an Update for those waiting for an answer or pawing through old threads on google in the future.(hi!)

As it would turn out some monkey who rebuilt the turbo previously either forgot to put in the oil drain gasket, or intentionally didn't bother.... I ordered a new one from Subaru (PN: #15196AA060) and I will be putting it on my TD04 to see if it fixes the issue. Seltzer, I would check to see how that gasket is looking on yours.

Re: TD04 turbo smoking

Posted: Sun Aug 21, 2016 8:42 pm
by Legacy777
Thanks for the update. Let us know if that completely fixes your issues.

Re: TD04 turbo smoking

Posted: Sat Aug 27, 2016 11:30 pm
by Mister Anderson
If that doesn't solve the problem I would check the seal(s) on the back of the passenger head where the oil distribution plate is. Last December the large plastic (I believe it was plastic, or was at some point) seal ring for the back of the cam went bad. It was leaking fairly heavily onto the up-pipe causing a lot of smoke.

Re: TD04 turbo smoking

Posted: Tue Nov 08, 2016 7:53 pm
by Pielikey
Hey guys,

Sorry about the incredibly old thread bump (college & work keep getting in the way of this project!) but I didn't want to leave you all hanging. As it would turn out, the oil drain gasket on the bottom of the turbo was in fact the issue. We remade one out of some thicker paper (specifically a school folder) & it seems to have gone away.

Thank you all for the help & advice, and I hope this can help someone in the future.

Re: TD04 turbo smoking

Posted: Mon Nov 14, 2016 6:18 pm
by Legacy777
Thanks for the update and letting us know what the culprit was.