Subaru VF46 turbo failure

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Apr 16, 2025
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Car lost the turbo right before this sample was sent in. No visible damage to turbo wheels, has slight shaft play and doesn’t spin as well as it should.

I’m concerned about the very high levels of copper and potassium (and others) with only 300mi on the sample.
 
Install a new turbo, change the oil, test again. High copper is to be expected from the turbo bearings, and 17 isn’t really that high - we’ve certainly seen worse. Also high potassium, as they said, is a sign of a coolant leak, but yours isn’t that high that the oil was completely contaminated - those are parts per million, after all. This is a 163,000 mile car - there could be other sources of coolant contamination, like a head gasket, and you may need to chase those down, once you have verified a trend.

New turbo - remove the source of contamination.
New oil - remove the contaminated oil.

Run it, and test again.
 
Install a new turbo, change the oil, test again. High copper is to be expected from the turbo bearings, and 17 isn’t really that high - we’ve certainly seen worse. Also high potassium, as they said, is a sign of a coolant leak, but yours isn’t that high that the oil was completely contaminated - those are parts per million, after all. This is a 163,000 mile car - there could be other sources of coolant contamination, like a head gasket, and you may need to chase those down, once you have verified a trend.

New turbo - remove the source of contamination.
New oil - remove the contaminated oil.

Run it, and test again.
Appreciate the input.
 
I would make sure there are no screens in the oil line to the turbo or variable valve timing on the heads. They tend to plug up.
 
I’m probably one of the few that kept all screens in after turbo failure on my EJ. I like to live on the edge! Put another 110k+ miles on it before it was rear-ended and I sold it. Stuck with xW-40 oils the rest of the time that I owned it.
 
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