Nasty Oil Leak Under/Behind Turbo
 

Hope its okay to put this in the Boosted section- The stock 1981 301 Turbo car I purchased had a large amount of oil sludge on on top of the valley pan and around the distributer base. The turbo has been rebuilt and the end-play checked out at .003 and the impeller was not oil stained.

I see the drain pipe that goes back to the valley pan had red silicone used to seal the drain pipe flange back to the turbo housing and maybe it should have a specific gasket, but I wouldn't think oil would work its way out the flange when it would more easily drop out the drain tube.

I replaced the intake, valley pan, valve cover (1/4 thick), and turbo gaskets, but haven't unbolted the drain tube as all I could do is add more silicone and would think the oil would rather drop out the drain tube than work its way out of the drain tube flange. I think I'll reseal that anyway.

Any suggestions on where this large amount of caked-on oil sludge came from? Hope this is the right forum, though the 301's don't have a great reputation due to the siamese ports.

All draw-thru Turbochargers need a carbon face seal between the compressor wheel and the CHRA (Compressor Housing Rotating Assembly).

The oil comes out of the CHRA, leaks at the compressor housing which has no gasket there, (just a slip on fit with fasteners) and drips onto the Valley Pan. Whoever did the rebuild on the Turbo, (ask them if they replaced the Carbon Face Seal that is stock on those turbos). Turbos have not had carbon face seals for at least 25 years.

The seal is typically located under the compressor wheel and between the wheel and the cast iron drain housing.

Tom V.

Ok - thank you very much for the information on the likely source of the leaking.

There is a tag on the housing that says it is "factory rebuilt by Garrett" and gives a part number and serial number. When I search for the part number it comes back as the factory turbo for a Pontiac.

The housing itself is clean and doesn't look to be 25 years old or older on the rebuild. Would seem that not having a seal would have been a nightmare for warranty issues back in the day, so maybe there is a different type of seal used in the modern turbo world. Just having a slip fit where oil is involved doesn't seem so good. Using red RTV to seal the drain tube flange doesn't seem like a factory approach though. Maybe an attempt afterwards to slow the leak.

I could call Garrett and give them the serial # and part number though not sure what info they would give me on it. The fellow I bought the car from was not mechanically inclined and I couldn't get any better info on the car and had to price that in as best I could. He had owned the car a short time and realized he was in over his head and was believable.

It was a nightmare for the OEMS in the late 70s with the Draw Thru Turbocharged
systems. The Turbos were not balanced properly and made compressor noise, the carbon Face seals were not durable, and the overall performance was poor.

Will be interesting to see that Garrett put into your Turbo.

Draw thru Turbo Systems did not work well in the early stages of Boosting in the Turbo World.

Tom V.

Looks like Garrett Airesearch has gone through many mergers and is currently owned by Honeywell. I haven't been able to find a way to contact them and other rebuilder services come up on searches. I take it they dont' rebuild them anymore or they would be searchable?

Not seeing any contact info for the turbo newbie. Maybe you could have a suggestion? Sounds like it needs rebuilt again, either way. It does have .003 axial movement on a spec of .002-.006 and no oil stains on the impeller though.

They have not gone by the name Honeywell for several years.

The new name for the Garrett Turbo Company is:
Garrett Motion

https://www.garrettmotion.com/turboc...orks/advanced/

I would contact them using this link:

https://www.garrettmotion.com/contact/

Tom V.

Ok, very awesom.e- I filled out their contact form with P/N and Serial Number and will be hearing back from them, according to the auto-responder email.

I haven't restarted the engine but cranked it over as part of doing a compression test and already see fresh oil on the back of the cleaned valley pan.

The drain-tube flange did have a gasket in it, and red silicone where someone else had been into it, probably looking for the leak and had added red rtv to the gasket. The torque figure is in question as the service manual calls for 45 lbs, if I'm reading that correct, which seems like a huge amount for a 5/16 or 8 mm bolt - can't remember which as some bolts metric, some are standard.

Hope you hear back from them.
Tom V.

I used to work with a couple of the Garrett and IHI Turbo Guys but much more often with the Borg Warner Turbo Team. The Director of Turbo Operations Tom Grissom just retired in the last year or so from Borg Warner.