Background info: Turbo is T4/T67 and is 5 years old; it probably has the equivalent of 200 miles on it because it’s on a race-only car. Maximum boost it has created is 30-32 psi, that I know of. I noticed a leak on the turbine housing so I decided to investigate. I pulled the turbo off and checked shaft play and it wobbled like a top. Endplay seemed ok but radially the sumbitch wiggled more than I thought was normal. So I decided to pull it apart and here’s what the shaft looks like. The last time I started the car up was last Saturday and oil pressure read higher than usual; it was at 90+ psi when cold and at idle. In the past that was 75 psi. Sooo, I don’t know if these two things are correlated. I pulled the oil pan and it looks clean, no metal shavings. Only thing I notice throughout the motor is that oil is definitely mixing with another fluid, either water or fuel. I think this because of the smell of it and it leaves a grayish residue in the oil pan.

Questions:
1. Why would I see oil leaking onto the exterior of the turbo? People say “seals”. When I tore the turbo apart I saw one part that resembled a seal and that was a rubber o-ring about 2” in diameter that sits in a groove on the center cartridge, it looked fine.

2. Does the shaft look damaged? I notice it is blued and there appears to be grooving at the portion of the shaft closest to the turbine wheel.

3. Any thoughts or hints are welcome, of course.

Thanks brosefino’s

 

thats alot of heat in that shaft.

 

what size oil return and is the motor vented? the only reason i ask is if the return is to small the crack pressure well try and push the oil back up the return cause the oil to bake in the turbo, causing o-ring failure.

 

The return line is -12 and the motor is vented and not drained back into the motor. I'll check the oil feed line and return line to make sure they're not clogged.

 

every non ballbearing turbo ive rebuilt has had the blue/black color on the shaft all we do when rebuilding is take 2000 grit and sand the whole shaft. The seal that leaks on the rear is the snap ring that seal the oil from going into the exhaust housing. i took one of your pics to show you.

 

Ahh yes I noticed that part. What a weird type of seal! Thanks a lot that's great info! Now how can I check if the slop in the shaft fit is out of spec? What should the clearance be between the shaft and the bearings?

 

you could get all the parts for cheap and that seal just replace it now