Hello again everyone!

So the 130K Mini I help maintain is being a pain again! It seems it can't make it two weeks without needing $200+ in replacement parts...

I think the turbo CHRA is dead now, it won't fully boost.

The thing that started it all was what I assumed to be the turbine housing failing, the wastegate flapper was so carboned up it wouldn't seal tight. The symptoms were low, low boost ~6psi and it would occasionally limp-mode on high gear low RPM pulls. We replaced the turbine housing, wastegate actuator, oil lines, and all the turbo associated vac lines. Success! It worked great again, for a time.

Next, the valve cover failed, or more specifically the irreplaceable orange diaphragm disc shelled itself. As far as I could tell it was attempting to pull massive vacuum on the crank at all times. It would bleed out air after you shut it off, "pshhhhaaaaaaaaaaaaaa...." A new valve cover fixed this. Who's idea was that, anyway? Whole valve cover for a little rubber disc

Then it was misfiring so bad it wouldn't stay running, new $70 plugs less than 10k since the last identical set fixed this. I guess it huffed a lot of oil while the valve cover was out and really fouled the plugs. I don't think they were anything special, just NGK bk7re or something close.

Now we're back to the low ~6psi boost problem again, with a very disturbing fire-truck like siren or squeal while cold. Right now, it seems to go away when hot, but boost never comes back as it should. It's very much a supercharger like whine, the sound you'd expect if the turbine or compressor got wacky.

I've always assumed this thing sat in a mist of oil at all times, which jives with my buddies claims that it'll eat a quart in 1,000 miles and has done so for 70k+. We just replaced a cracked turbo inlet tube, and I'll be dammed if it's not covered in oil within a few dozen miles. For so much oil to be getting so far out in the intake plumbing, plus the strange sound and no boost, I'm thinking it's had enough and is about to really let loose. There doesn't seem to be much shaft play at all, no runout, though it does feel a bit scratchy. Turbo too small, hard to feel it up...

As all these expenses have happened within the last 6 months or so my friend isn't really super stoked to spend $600-700 on a new CHRA and possibly more on a compressor housing, and I really can't blame him.

I've found way cheap Chinese CHRAs for ~$200 shipped, which is pretty dang reasonable. Sounds funny, but I myself drive a turbocharged miata using a $218 ebay china turbo that's still going strong at least 20k miles later, without eating all the oil the mini does...

Have any of you heard or even replaced your turbos for these cheaper Chinese ones, and do you think they'd last 20-30K miles till this mini motor is due to eat itself again? While it's easy to find china turbo stuff for the miata, google's having a hard time with the mini...

Thanks for reading!

 

I've found that when crankcase pressure is positive, the turbo oil doesn't drain back into the crankcase, it goes thru the seal and into the turbo air intake chamber. If you see oil in the turbo air inlet chamber, this source can be verified by ensuring no oily hose from the driver-side PCV port.

How to fix it? Ensure crankcase pressure is zero or negative --- usually the PCV system. Sometimes an OCC connection causes it too --- if the manifold is blocked.

 

You replaced half of the turbo.

More than likely the turbine shaft seals are loose enough to let the oil blow by.

Take the unit off and send it for a rebuild. Should be the cheapest option.

 

I hadn't considered this causing more turbo oil consumption, but I could easily see that happening.

The PCV system on this car is just the little copper airflow sensor/inlet on the turbo inlet tube, the actual PCV valve is in the valve cover, and the tube on the passengers side cover down to the intake? Is there another solenoid or something on the intake manifold side?

I also hadn't considered a rebuild, do you know of any good companies to recommend?

 

I dealt with JMTurboCooper for my replacement. They do rebuilds also. Really liked working with them.