Turbo Leaking Oil

I've got a relatively new GTB1756VK that I've been running on my BHW for about 10,000 miles. In the last few months, it's only been pushing a max of 25 psi because my tune hasn't been finalized. That's only when flooring it, it usually runs much lower than that.

Today, the ECU kept going into limp mode, complaining about "boost control level not reached" or whatever. When I looked under the hood, there was a mess of motor oil around the turbo and the ProVent was full of sludge. I took off the turbo inlet pipe, and the compressor housing is dripping with oil.

The compressor wheel has maybe 0.25mm of wiggle in every direction, it's minimal. It turns freely, there's no binding whatsoever, even if I push it in any direction while turning. The engine otherwise appears to run just fine.

What causes the turbo bearing seals to fail? Is that what I'm looking at here? Is it rebuildable? I spent a pretty penny for a custom-built turbo that supposedly has a billet compressor wheel and "uprated" seals, I kinda expected it to last longer than this under unabussive circumstances.

That amount of "wiggle, side to side is normal, front to back play is BAD but a tiny bit might be normal depending on the journal bearing turbo. As for oil in the compressor housing, that’s CCV most likely. One way to know is to divert the pipe into a make shift catch can, monster energy drink can (tall) with the hose into the top about 1-2 inches into the can with a rag over top and a few zip ties, it will be enough to tell in 50 miles if you have excessive oil blowby. If you do, that’s probably blowby from the rings maybe. A Leak down test will give you better information on those vs a catch can. But it’s a cheap start. Most journal bearing turbos have that side to side play, my gt2052 has almost none at all but that’s not necessarily normal for other turbos like yours. Drain the intercooler and measure out the oil, 1 cup is normal, 2 cups, not so good, more than that is an issue, Drain the intercooler, make shift catch can, run for 50 miles and see which one has more in it. The intercooler should have a tiny bit but if the catch can has a good amount in it, there is your issue. Unless you see excessive EGT's from larger fuel delivery and injection the turbo is probably fine.

I have a compression tester and a leak-down tester, so I can run those tests tomorrow. I have an EGT gauge hooked up, and I haven't noticed anything undue recently. My boost and EMP gauges aren't currently hooked up, but it's trivial to get them working again. That might shed some light too. This all just kinda happened suddenly this afternoon after months of no issues whatsoever, it wasn't a gradual failure. I did let it idle for an extended period a couple days ago, so the cylinder walls may have glazed over a bit. But even after the engine was freshly built (10k miles ago), it never exhibited this much blowby.

Guess I have a lot of diagnosing to do... thanks for the insights!

What follows is what I’ve gleaned from reading on these forums over the years: jfettig, shortysclimbing, mchill, etc all know WAY more about turbo stuff then me.
In general the turbo oil seals only seal when exposed to boost pressure.
In more cases then not the seals actually let oil get sucked into air stream when the turbo is at 0 boost (can sometimes even be at a slight vacuum) which only occurs at idle rpm’s.

Anecdotally seems like “custom” turbos have a much higher rate of TGW then out of the box OEM spec ones.
Hope you can sort it out, you’ve certainly put a lot of time and energy into that car. Sucks to get derailed.

Some oil in the compressor housing is normal, and it's hard to imagine how any significant quantity would hang around without being blown into the engine. Oil on the exterior of the turbo is often a leaking oil supply or drain tube issue.

Since it's a recent issue - check the under-boost basics like vacuum strength at the actuator, VNT arm moves correctly if you manually apply vacuum, and check for any obvious boost leaks.

Turbo seals are a dynamic system with no "100%" mechanical sealing like a radial shaft seal.
They need a functioning pressure level on both sides of the turbo and a free flow oil return.
A malfunction in crankcase venting can cause excessive oil spillage per example.

Crankcase pressure must not exceed 0.6-0.7psi, otherwise this will already lead to an possible oil problem and turbo damage.

Chinese turbo?

You may well be looking at two problems that may not be related.
The sludge build-up needs to get diagnosed if it is way more than normal.
Maybe your fairly fresh rebuild needs more miles to seat those rings, etc.
Your turbo sounds like it is leaking badly. Don't risk your engine to a potential runaway.
Return it to the company that built it for a replacement or a refund. They should back it up.

flee said:

Maybe your fairly fresh rebuild needs more miles to seat those rings, etc.

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There is no such thing as a "seat in" process on the sealant ring in a turbo.

any turbo built properly can be pusshed to its limit right out of the box, EGT,boost, whatever

only cams/lifters, piston rings, clutches, brake rotors, tires, require some form of a brake in or gass off or bed in procedure, i have never heard of a turbo needing time to brake in, thats madness, turbos are built with very high degree of tolerance. if it was going to fail ,it would do so in the first seconds of full boost or EGT, or in 10,000-20,000 hours of work.

majesty78 said:

There is no such thing as a "seat in" process on the sealant ring in a turbo.

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At first glance, I thought he has 10k miles on the whole engine. My bad.
The blow-by problem may well be rings, however, and is what I meant.

To clarify, the entire engine does have 10k miles on it since the fresh build, so yes, there's still some breaking in to do with the rings.

I retained the CCV heater when I laid out the components for the new turbo, and I tested it to make sure it was still functional.

It's not a cheap Chinese turbo, it's a custom build from X-man turbos.

What happened is I left the engine idling for like an hour by accident (I forgot it was idling and I got distracted) in ultra-cold temperature. The coolant and oil temperature gauges dropped to their minimum reading during this time, which is an ideal condition for glazing the cylinder walls. Shortly after that is when the oil build-up on the outside of the turbo and the sludge inside the ProVent became apparent. I cleaned out the sludge and removed all the evident oil in the intercooler hoses, and made sure there were no boost leaks. I've since been driving it somewhat aggressively to try and get the piston rings seated again, and the oil leak appears to have disappeared. The turbo has slowly returned to proper operating condition and now runs perfectly again. Oil consumption is back to negligible, and the engine is running awesome without ever going into limp mode.

Lesson learned: don't idle uselessly in super cold weather.

QuickTD said:

Are you sure your provent didn't freeze? CCV gasses contain lots of water vapour, that's why the original CCV tube has a heater where it meets the cold intake air.

If the CCV system freezes it will pressurize the crankcase and blow lots of oil into the intake via the turbo. As has been said, the turbo has no real seal in the intake side, just a slinger to throw the oil outward away from the shaft. It needs positive pressure in the compressor housing and free drainage or it will leak.

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That may also have happened, since the ProVent is on the cold side of the engine and the 1 hour of idling was on a morning where it was -30 outside. It's baffling how cold this engine runs when it's idling in cold weather. There's NO waste heat whatsoever.

Do you have a oil PSI gauge? if you dont, get one lol, i recommend AUBER digital that way you know EXACTLY what pressures you have, your breaking in a new engine and will be for some time lol, i would expect a bit of oil loss, but you should have proper pressure, thats all that is important.

Mongler98 said:

Do you have a oil PSI gauge? if you dont, get one lol, i recommend AUBER digital that way you know EXACTLY what pressures you have, your breaking in a new engine and will be for some time lol, i would expect a bit of oil loss, but you should have proper pressure, thats all that is important.

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Yes I have an oil pressure gauge. Also running a BRM oil pump gear on a BHW with BSM delete, so pressure is plenty adequate.