M1 15w50 in a turbo subaru 2.5 liter - 3 season?

[AndyH]

I think I'd start with a 'thick' 30-weight such as GC, or a 'thin' 40 weight such as M1 0W-40. Maybe even step up to Shell Rotella-T 5w-40. But I'm just not seeing the need for the M1 15w-50 in a stock LGT in PA. My $0.02

 

[JoeFromPA]

Fair enough: I'm planning on running RTS 5w40.

I ran PP 5w30 and did a UOA with Blackstone (no TBN, since it was a 3600 mile UOA). It looked just fine.

I'm not worried about any quality synthetic holding up to my current intervals, overall. I'm worried about those oils not holding up in the #2 cylinder and turbos under unique circumstances. I'm guessing that i'd never be able to tell if an oil temporarily failed in those instances, using a UOA.

Joe

 

[bluesubie]

Joe,

If most of the LGT failures are due to the screens becoming clogged, then it's not a viscosity issue correct?

Or are you thinking that they're being clogged because the oil is failing due to the viscosity index improvers in the oil failing and turning to sludge? Maybe a deposit problem too?

I did a quick search on Opie and noticed he was using Motul a few years ago.

FWIW, I believe Terry Dyson recommends mainly 10W-30's to most of his customers. That's only based on what I've seen from his customers posting their uoa's here. I saw one modified STI owner running RLI HD 5W-40. Other Subaru turbo owners are running RLI 10W-30, Rotella 10W-30 (every 3,750 while under warranty) and some other 10W-30's, IIRC.

-Dennis

 

[JoeFromPA]

Hey Blue,

I think the Turbo is failing because the screen is becoming clogged and the existing lubrication in the turbo is insufficient to protect the bearings. It's not completely clogged. The stock turbo feed line is pretty small as well.

Also worried about the #2 cylinder ringlands.

I didn't think Opie's turbo failed, only that he was contributing to the thread...