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Hi fellas,

Looking for the community's opinions on whether I should start looking for a new turbo at this point. A little history:
  • 2016 WRX STi purchased new
  • At ~8k miles I put an OTS Stage 1 tune on using a Cobb AP. All readouts looked good, tune seemed to take well to the car.
  • At ~12k miles I installed a 3" catless Invidia downpipe to smooth out the flow path directly after the turbo. Wrapped the intercooler w/ gold heat reflective tape, the turbo with a turbo blanket, and the downpipe with heat wrap. Loaded an OTS Stage 2 tune from Cobb. Intake temps were in line with stock, injector duty cycle was just below max, no signs of knock.
  • During this time I had an opportunity to take the beast on a track, unfortunately it was about 105 degrees ambient and she lasted about 4 short laps before my coolant temp hit critical. In retrospect this was of course pretty dumb, but it was a lease going back at 45k miles :D
  • At 42k miles I replaced the clutch to avoid dealer labor rates when I turned her in. Intercooler was free of oil at this time. I also put the stock downpipe back on, removed the turbo blanket, and loaded a Stage 1 tune back on. Oil change as well.
  • Typically for me when it comes to decisions about cars, I changed my mind :) and bought the car off the lease. I was going through a crazy time in my life and went just over 7k miles without an oil change (typically I do every 5k) which brings us to this week.
I began tearing down the car for a thorough tune up (and to put my Invidia downpipe back on :D) and noticed a decent amount (pools about the size of a silver dollar) of unsurprisingly black oil in the intercooler body and rubber feed pipe on the turbo side of the intercooler. The car was also very low on oil, no oils showing up on the dipstick at all.

Disclaimer: I know there were many things I did that make me seem like an idiot. While I am not a race mechanic, I know how to run a performance car, and any missteps I took during ownership of this car I believe I am aware of. I am not saying I know everything, and feedback is welcome, but just know that I am disappointed in myself for how I have neglected this amazing vehicle and promised myself to do better in the future (thus the thorough tune up).

With that out of the way, I come to the main reason I am making this post. I drive hard, nearly daily, with this car, typically hitting WOT through a few gears multiple times on every drive. With this in mind, and the history of the car above, do you guys think that at ~50k miles my turbo seals are gone? If I have to do the turbo I would rather do it now, while I have everything off the car.

I do not however want to do the turbo if my ringlands are blown (possible reason for low oil). Since there was a decent amount of oil in the intake path I do not believe this is the case, but would be an expensive mistake if I replaced my turbo on a blown engine.

I also read oil in the intake could be cause by spirited driving causing the PCV system to suck oil from the crankcase into the intake as it vents. I am not very familiar with the PCV system but as mentioned, I never saw ANY oil in the intake before this, and have been driving hard for the life of the car.

So what do you think guys? Should I order a turbo as my reasoning is telling me? Or should I put her back together as is, monitor oil levels/boost pressure/intake temps, and check the intake for oil going forward? Oil in the intercooler decreases its efficiency and as you can see from my mods I put a high value on keeping the engine cool to mitigate risk of ringland failure so I am hesitant to NOT replace the turbo immediately, but again, expensive if I am wrong.

Sorry for the novel, diagnostics can be complex :) Thanks for all replies in advance guys!!

Speedslayerr

P.S. If the rec is to replace the turbo, recommendations are welcome :)
 

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No, do not replace a turbo that doesn't need to be replaced, and at this point you do not know it does.


[*]At 42k miles I replaced the clutch to avoid dealer labor rates when I turned her in. Intercooler was free of oil at this time. I also put the stock downpipe back on, removed the turbo blanket, and loaded a Stage 1 tune back on. Oil change as well . . .went just over 7k miles without an oil change (typically I do every 5k) which brings us to this week
. . .

[NOW] noticed a decent amount (pools about the size of a silver dollar) of unsurprisingly black oil in the intercooler body and rubber feed pipe on the turbo side of the intercooler. The car was also very low on oil, no oils showing up on the dipstick at all.
. . .
I drive hard, nearly daily, I do not however want to do the turbo if my ringlands are blown (possible reason for low oil). Since there was a decent amount of oil in the intake path I do not believe this is the case,
. . .
I also read oil in the intake could be cause by spirited driving causing the PCV system to suck oil from the crankcase into the intake as it vents. I am not very familiar with the PCV system but as mentioned, I never saw ANY oil in the intake before this, and have been driving hard for the life of the car.

Compression and leakdown to rule out ringland issues.
Check turbo bearing play fpr sign of issues.

Yes driving hard can cause PCV system to eat oil and the "7K" dirty oil means it was what you found.

I'd be more concerned about bearings wear from driving hard with low oil. Turbos cost money, but are still easier to replace and cheaper than a bottom end. How low was it? If not yet discarded you might send a sample for analysis.

Perhaps a good AOS is in your future?
 

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Yeah I agree with mheyman. Your turbo is fine.

I used to get pools of oil in my intake tract when on the stock turbo when I drove hard. You are likely overcoming the stock PCV system and causing it to pool in your turbo, this is pretty normal when doing what you are doing.

If you aren't having a lot of knock or weird issues, I don't think your ringlands are bad. Burning oil is just part of owning a Subaru.

My wifes 2011 WRX with just Cobb OTS stage 1 + Intake burns ~.5 a quart in 3500 miles. My STi burns more, but its built sloppy.

I'd get an AOS if you intend to drive it this hard, or better yet a dual catch can system.
 

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Discussion Starter #4
Awesome advice and analysis, thanks guys.

I haven't drained the oil yet, planning on doing that in the next couple days, will report back on the level. Sending some out for a sample is a great suggestion, as well as the compression/leakdown test. Forgot about that one.

As far as an AOS, I never considered it but it looks like I could definitely benefit from one! Assuming the leak down comes back clean I'll decide whether to get an AOS based on the next few thousand miles of monitoring.

Thanks again guys!
 

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I'd go AOS to minimize the chance of running low on oil - again.

My IAG works extremely well. But, I won't tell you it is a fun thing to have under your hood. Modern cars are tight enough without adding stuff . . . I might use an unheated one to eliminate some of the hoses if I lived where there was no winter.
 

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SMOKE! Where's the (mention of) smoke? Does it smoke under any circumstances? It should smoke if the seals are gone under boost. Unlikely it's ringlands. That's pretty obvious.
Oil can sit in a puddle almost indefinitely. You must install an A/OS. Have it drain back to the crankcase. Add an oil cooler! A must if you track it. Upgrade the radiator. I have a Ron Davis in my race car and they have a combo version that's trick.

mheyman said most of it quite well.
You still have a lot to evaluate for a good, basic diagnosis. What do plugs look like?
 

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Like others have said, your turbo is most likely fine. I'd bet the oil in your intercooler is just from the PCV system. It will collect there over time due to normal blow-by these motors produce. The more you are in boost the quicker it might accumulate. That 7k oil change interval didn't help either as that oil was most likely sheared down and lost some viscosity. I suggest getting an AOS. I have the IAG competition version which deletes the entire PCV system and vents the crankcase pressure to atmosphere. My intercooler has been bone dry ever since that was installed and I never have to worry about any oil or blow-by re-entering the engine through the intake. Definitely provides piece of mind when out on track too.
 

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Oil in the intake track is pretty normal on forced induction cars. If the car is performing normally under boost and the turbo doesnt have shaft play or oil in the hotside, then i would not suspect a turbo being bad. As for your low oil, i highly suggest you start monitoring this. It cant hurt to replace the PCV valve and clean out the intercooler. I also think you should run a compression and leak down test to rule out ringlands being the cause of oil consumption.
 
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