turbo seal question

[grey ghost]

The seals on my k27 are shot to the point that my downpipe is completely filled with oil. If I took it off today I could pour 4 quarts out of it. With that said, could seals damaged that badly cause a difference in metered air vs air reaching motor? In addition to lossing oil, can I be losing air thru the turbo right out the exhaust as well?

Thank.

[grey ghost]

No one? Was is a stupid question?

[Kyle in NO]

It won't affect metered air because the oil passages are pressurized. However, 4 quarts of oil in the downpipe reaches a previously unknown level of fuckage.

[grey ghost]

So I've pulled the turbo with the leaking seals. The turbo spills freely with absolutely ZERO shaft play in any direction. Does this firm shaft, no pon intended, and severely leaking seals go together. I was expecting there to be significant shaft play.

[Kyle in NO]

They aren't rubber seals that just go bad, typically they are metal bushings that seep slightly. If there is no shaft play, then it would be unusual but not unheard of. There could even be a crack in the turbo housing allowing oil to enter the housing.

[Brad D.]

Both the compressor and turbine shaft seals are a piston ring type seal. The turbine seal is 3 in the pic below.


Here is a good article with better pictures.

http://www.turbo-mopar.com/forums/showt ... -With-Pics!


Is this an original turbo or had it been rebuilt? It sounds like the turbine shaft seal could have failed completely if it's leaking that much oil although even a small seal problem can leak a lot of oil as it would be forced out under oil pressure into the exhaust. It is odd that it has no shaft play but it may or may not be related. I think the only way you are going to get to the bottom of this is to tear the turbo down and inspect the seals.

[EricF]

Also check crankcase pressure and turbo oil return line. A clog, or excessive crankcase pressure will push oil past that turbine seal. With that much oil, the turbine seal may be cracked or missing altogether. Is there any end-play to the turbo? End-play can exacerbate oil pushing past the turbine seal as well.

[grey ghost]

Also check crankcase pressure and turbo oil return line. A clog, or excessive crankcase pressure will push oil past that turbine seal. With that much oil, the turbine seal may be cracked or missing altogether. Is there any end-play to the turbo? End-play can exacerbate oil pushing past the turbine seal as well.

There is zero play. I mean ZERO. Thats what has me puzzled....

[EricF]

Loosen the oil cap, and rev the engine under the hood. See if the cap gets pulled down or if it floats. If it floats, then under high load the crankcase pressure is likely quite high... Oil drain is a gravity-based system and anything in the crankcase besides vacuum will basically severely back up the oil in the turbo's bearing housing. You'll lose oil and smoke like crazy even if you have a perfect turbo. You may have crankcase ventilation issues or blowby issues. Checking the ventilation system and doing a leakdown test wouldn't be a bad idea if this is the case.

Also, with that much volume of oil I'd be tempted to extend the search to in front of the turbo as well. It sounds like it's still liquid though... Are you losing the oil just sitting at idle, or is this after a drive? If it's under load then the oil would most likely come out as smoke and cake on the interior walls of the turbine and exhaust. If it's liquid, that suggests it is happening at idle or light loads...

I've also seen bearing housings crack into the turbine side, but never resulting in that much oil leakage. Also seen turbine shafts break and the turbo will have 0 play if you only check it from one side. Does the turbo still build boost and otherwise work properly?

Very puzzling. There's some more stuff you can do without pulling the turbo, but I'm guessing that will end up in your future.

Disclaimer, based on many years of Volvo experience...

[turbodan]

There is always shaft play. Brand new turbos have shaft play. This is the nature of hydrodynamic bearings. If there is no play there is metal to metal contact between the shaft and journal and no room for oil. Try wiggling harder.

In any case, oil in the downpipe is almost certainly the hot side oil seal. This seal is independent of the journal bearings that support the rotating assembly. The oil seal can fail for no reason with no effect on the bearings.

[grey ghost]

The turbo has already been replaced. Now, at idle it still blows light smoke and doesn't idle very well. I'm wondering if all the burning oil has destroyed my o2 sensor. I plan on replacing both the stock and wb o2 sensors. Also I'm thinking I may be burn residual oil. may need to put some miles on it I hope. will check for shaft play again. I will check the oil cap trick.

I just changed the oil last weekend and there was no coolant in the oil.

[Havokin]

Did the new turbo fix the oil puking? I am running into a similar issue on a 745i (ran fine when I first got it running with no smoke) then the next time I went to run the engine I was billowing with a ton of oil in the intake and exhaust piping. Wondering if that is similar or if I am looking at a completely different issue

[grey ghost]

Its blow-by and crank case pressure. You need an air/oil separator on the valve cover breather hose.