940 slight smoke from exhaust side

Yesterday I finally buttoned up and started a 940T wagon project car I've been working on since March. She starts strong and even drives seemingly fine for the most part. (I can't drive her long or far since I don't have her registered yet... only around the block.)

But there is slight smoke coming off the exhaust side after idling for several minutes and after driving briefly. There is more after driving, but not like plumes of smoke or anything. The car's driving and idle do not appear to reflect any problem and I had the head decked and put a new head gasket on just a couple weeks ago. However, I am trying to be cautious with running her too long as currently there is no temp reading getting to the gauge and I don't want her to overheat...

There is no noticeable smoke coming out of the exhaust at the tail pipe.

I am not running gaskets between the turbo and the downpipe, nor between the exhaust manifold and the turbo - did I miss a gasket in either place?

Also, there was a failed seal for the coolant return banjo bolt when i first was filling the cooling system. I replaced the seal and it is not leaking now, but it did leak a good bit of coolant around that area. I've thought that the heat of the exhaust side could be burning off that coolant?

I did not rebuild the turbo but the car has 124k miles on it. I've also thought it could be a bad bearing inside the turbo...

any thoughts or ideas for troubleshooting? Particularly if I missed a gasket. thanks everyone

Are the exhaust parts brand new? Sometimes they are packed with a bit of something on them to prevent rust, which burns off when things first get hot.

I found the culprit - leaky valve cap, oil spilling onto exhaust side and burining. sorry for the thread!

mschultz373 said:

I found the culprit - leaky valve cap, oil spilling onto exhaust side and burining. sorry for the thread!

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No worries, maybe someone in the future will find it and solve their issue the same way!

Valve cover has no baffle in side of it. Also check your flame trap, if its not working right you might have crank pressure and its going to find the least resistance opening or openings.

mschultz373 said:

I found the culprit - leaky valve cap, oil spilling onto exhaust side and burining. sorry for the thread!

Click to expand...

Same thing happened to me when I installed a new oil cap gasket. Of course my first assumption when I found the oily valve cover was that my rings were toast, but some guy passing by suggested tightening the valve cover. It turned out I had it on some absurdly low setting like 20 inch pounds because I didn't know that it was supposed to be 4-6 foot pounds when I installed it the first time. It's been fine since.

If you end up in the same situation and it doesn't stop leaking after 8 or 9 foot pounds, though, move on to replacing the gasket. I saw a thread on here where some guy cracked his valve cover after 11 foot pounds. Not the gasket, the valve cover itself cracked.

iamrolling said:

Same thing happened to me when I installed a new oil cap gasket. Of course my first assumption when I found the oily valve cover was that my rings were toast, but some guy passing by suggested tightening the valve cover. It turned out I had it on some absurdly low setting like 20 inch pounds because I didn't know that it was supposed to be 4-6 foot pounds when I installed it the first time. It's been fine since.

If you end up in the same situation and it doesn't stop leaking after 8 or 9 foot pounds, though, move on to replacing the gasket. I saw a thread on here where some guy cracked his valve cover after 11 foot pounds. Not the gasket, the valve cover itself cracked.

Click to expand...

Yeah I broke a valve cover stud trying to torque to 10ft/lbs per my buddy's advice. which was WRONG.

in any case, yeah, this 940 is a new project and I am going to get a catch can installed. the valve cap and gasket seem to be leaky regardless - it's leaking at low mileage with no boost (at stock psi).