My tuner just let me know that the car is burning oil at 6000+ RPM. He's unsure whether it's the oil control rings or the turbo, so i'm hoping that you guys have some insight.

- Garrett GT35R, unknown mileage, 1mm restrictor in oil feed, oil drain is good
- 70,000 miles on motor,
- Sometimes it puts out a smokescreen, sometimes it's not very much.

The variance in the amount of smoke leads me to believe it's the turbo, but i'd hate to send it in for service, only to find out that it's the motor. Thanks guys

 

Do you have oil pooling in the intake ductwork? If so, it is the turbo.

 

As stated, check the boost pipes and intercooler for oil. If there is oil present inside the boost pipes from the turbo (or inside the intercooler) then either:

A. Turbo is the culprit.
B. The PCV system needs looking at/fixing/rerouting.

If the intercooler is dry inside and the boost pipes from the turbo have no oil in them, then begin looking at the engine as a probable culprit.

In the scheme of what can go wrong on these cars, its a fairly easy one to diagnose.

 

Well, the PCV is eliminated. I learned about the virtues of crankcase ventilation when the car started smoking like crazy because the nipples on the oil filler neck were capped off, so it's vented to atmosphere.

I'll check the intercooler piping as soon as I get the car back in a few days.

I've been doing some reading about possible reasons for the high rpm smoking and I found that a lot of people that had issues with the oil control seals remedied the problem by added oil stabilizer or 'motor honey' to their oil. With our motors being as delicate as they are, I don't like trying new things unless they are well supported. Any input on the oil additive?

 

Motor Honey and the like work mostly by modifying the oil's viscosity. Thicker oil can't get past the seals as easily as thiner oil. Those oil additives typically also have ingredients that cause flexible seals to swell a bit, which can stop or reduce some oil leaks. But personally, I would only use them on a beater piston engine with bad rings and/or leaky valve guide seals.

Are you sure it's high rpms and not heavy boost that makes your engine smoke?

 

It could be. I'll find out in a few days. High boost would be a definitive signal of the turbo, correct?

Also, isn't it possible for the seal on the exhaust housing side to be worn, but the intake housing side to be intact, not allowing oil into the intercooler ducting while still smoking?

 

Whoops, I thought I posted this thread under OkinawaFD3S. I made a new user name because I didn't like having my name in my user name. Sorry about the confusion.

 

You can make a username change request somewhere on the forum. I cant quite remember exactly where.

 

Yes, but if oil is leaking on the turbine side into the exhaust, the smoke tends to be brown as the liquid oil volatilizes on the hot metal. In contrast, the smoke tends to be blue from combusted oil if the problem is on the compressor side or if an engine seal is to blame.

In addition to checking the intake ducts for pooled oil, check your plugs to see if they look coked up. If the ducts are reasonably dry and the plugs look OK, the problem is downstream at the seal on the exhaust side of the turbo.

 

That motor honey goo is not a really great idea. IMHO its more of a bandaid for an internal engine problem that isnt going to go away or get better with time.

Besides, if the viscosity thickens up, it may affect other things, such as the feed/flow through the metering pump and the metering nozzles, as well as the internal rotor oil spray system, and the time the thicker oil takes to get pushed to the bearings during a cold start up, causing accelerated bearing wear. Its not 100% that the honey stuff will cause those things, but it could increase the likelihood of any one of them becoming more prevalent.

If it was a newly refreshed engine with low miles (having ruled out the turbo) you'd probably stop and ask the question of why its happening in a fresh engine...?

EDIT: Re-read, you said its got 70,000 miles on it. Thats not really "new", so it may well be the engine, if its been well used.

Good luck

 

I finally got the car back after 2 months in the shop. It's been burning an insane amount of oil from maybe 75 mi of spirited driving. I think about half a quart. Pulled off the hot pipe and low and behold there's a good amount of oil in there. So I'm gonna be sending the turbo to garrett to have it exchanged. Thanks a lot for the really good info.

 

By "hot pipe" do you mean the exhaust (down pipe) or the duct from the turbo to the intercooler? Either way, that's a lot of oil to lose through a shaft seal. When you take it apart, the blades should be slathered in oil. Let us know what Garrett has to say.

 

The gt35r seems like it isn't built for the heat. I need mine rebuilt, my old FD had its gt35r rebuilt, now you.

 

I meant the pipe from turbo to intercooler. After talking to a local rotary guy, he told me that it's actually probably oil backing up in the turbo since the CHRA is about 30 degrees off of the oil drain being at the very bottom. I started taking it apart and it turns out that there's no oil in the intake pipe (filter to turbine), but oil in the turbo to intercooler pipe. Do you know what that means?

 

It sounds like the compressor shaft's oil seal is leaky. I don't know much about Garretts, but maybe the chra being 30 degrees out of alignment with the oil drain causes or at least contributes to the problem, causing excess oil in the turbo to the point where it pushes past the shaft seal and into the compressor area where the rotating blades then blow it toward the intercooler and ultimately into the engine. I wouldn't expect there to ever be any oil in the duct between the filter and the turbo.