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azimov308 azimov308 is offline
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Default N54 Rear Turbo Leaking Oil Out of Wastegate? - 01-06-2022, 08:22 PM

I'm having a weird problem almost a year after replacing my turbos. The rear turbo will blow smoke when stopped and when I'm driving it hard it misfires in mainly cylinder 6 but sometimes 4 and 5. There's oil on the outlet pipe and lower half of the wastegate actuator (shown in the picture). Could this be because of bad drainage or unequal turbo pressure? I can't imagine I have any shaft play this early.

https://imgur.com/a/P4VDd46

I've since installed a catch can, walnut blasted my intake valves, replaced the stock inlets with silicone ones. I also have an upgraded metal pcv valve and will be trying to replace the oil return line.

Any guidance would be greatly appreciated!
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CastleBravo CastleBravo is offline
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Default 01-10-2022, 12:54 AM

Where are you seeing oil in the photo? It's not obvious to me....

It's unlikely you have bearing wear on such new turbos, but the smoke when stopped points to some kind of PCV and or turbo seal problem.

Is the misfire a recent thing?
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azimov308 azimov308 is offline
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Default 01-10-2022, 07:37 PM

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Originally Posted by CastleBravo
Where are you seeing oil in the photo? It's not obvious to me....

It's unlikely you have bearing wear on such new turbos, but the smoke when stopped points to some kind of PCV and or turbo seal problem.

Is the misfire a recent thing?
You can see dried up oil on the lower half of the actuator and on the outlet pipes where it connects to the compressor housing on the rear turbo.

The misfire is a recent thing.

Could it be because of an old valve cover? I can't imagine it's a turbo oil seal problem because of how long I've had it and the fact that it doesn't blow smoke while I'm driving normally.
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CastleBravo CastleBravo is offline
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Default 01-10-2022, 08:06 PM

Quote:
Originally Posted by azimov308
You can see dried up oil on the lower half of the actuator and on the outlet pipes where it connects to the compressor housing on the rear turbo.

The misfire is a recent thing.

Could it be because of an old valve cover? I can't imagine it's a turbo oil seal problem because of how long I've had it and the fact that it doesn't blow smoke while I'm driving normally.
My initial thought based on your symptoms was valve cover gasket..you can get leaks into the spark plug well and that is also known to cause misfires. Depending on your mileage if you haven't changed your valve cover gasket...you'll need to at some point :D

have a look in your spark plug holes on the affected cylinders, take a coil out and if you see oil in there...you know your valve cover gaskets are bad.

If the valve cover gasket isn't sealing it will result in all kinds of PCV issues, which will in turn easily result in smoking. There isn't anything inside the valve cover itself to 'fail' the issue is they get clogged up with oil gunk and then don't function as they should.

Ensure your valve cover gasket is good/replaced, your valve cover is in good shape, and also the high side (hose at the back) flapper valve is okay along with your PCV valve.
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azimov308 azimov308 is offline
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Default 01-10-2022, 08:17 PM

Quote:
Originally Posted by CastleBravo
My initial thought based on your symptoms was valve cover gasket..you can get leaks into the spark plug well and that is also known to cause misfires. Depending on your mileage if you haven't changed your valve cover gasket...you'll need to at some point :D

have a look in your spark plug holes on the affected cylinders, take a coil out and if you see oil in there...you know your valve cover gaskets are bad.

If the valve cover gasket isn't sealing it will result in all kinds of PCV issues, which will in turn easily result in smoking. There isn't anything inside the valve cover itself to 'fail' the issue is they get clogged up with oil gunk and then don't function as they should.

Ensure your valve cover gasket is good/replaced, your valve cover is in good shape, and also the high side (hose at the back) flapper valve is okay along with your PCV valve.
I'll have a look, thanks!
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30FE 30FE is offline
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Default 01-13-2022, 07:34 PM

Quote:
Originally Posted by azimov308
I'm having a weird problem almost a year after replacing my turbos. The rear turbo will blow smoke when stopped and when I'm driving it hard it misfires in mainly cylinder 6 but sometimes 4 and 5. There's oil on the outlet pipe and lower half of the wastegate actuator (shown in the picture). Could this be because of bad drainage or unequal turbo pressure? I can't imagine I have any shaft play this early.

https://imgur.com/a/P4VDd46

I've since installed a catch can, walnut blasted my intake valves, replaced the stock inlets with silicone ones. I also have an upgraded metal pcv valve and will be trying to replace the oil return line.

Any guidance would be greatly appreciated!

At first glance, oil in that location is much more likely to be coming from the valve cover and falling down
however the lack of oil in the catch lip along the edge looks clean and clear, so, not sure.


If you run the engine with no cover/plastic over it, and also no cowling, the rear cylinders tend to be much more environmentally exposed than you may first realize. Water will drip down the windshield and its collect/drip point in the cowl (with shields removed) is right above the cylinder 6 coil pack

When diagnosing misfires on these cars, its very important to have very very clean components. You have no idea how many times I have seen my friends throw away "bad coil packs" that have dirt or oil in the tips. Or chased nightmare "injector" issues that turned out to be just an exceptionally oily plug hole. I would put much more of my gambling money on something along those lines being the problem, highly doubtful a bad rear turbo would boost fine but cause misfires unless it was shoveling half its feed oil past the front turbo journal bearing and sucking all that oil into the motor. Also check your plug gaps, and I would recommend running the NGK 97506 gapped to .020 or .018. Tried lots, never had a plug better than those on this platform. Don't expect more than 15k miles of life when running 12deg of timing tho, lol.

How do you know its only one turbo smoking? Do you have individual pipes with no cross at any point? How does the car boost, do you have any gate rattle?

EDIT: Oh yeah also check your ground posts on the valve cover. I had a multiple cyl misfire under load I chased for a few hours and almost threw parts at before I realized that the catch can line pulls on the pcv attachment point on the cover. This makes the oring slip out, and pcv oil drip from very high up on the cover. Could be your issue here, it may be following the catch can line from that loose attachment fitting before dripping down. Also may be dripping down between the cams there too. Worth a look.

Last edited by 30FE; 01-13-2022 at 07:39 PM..
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