subaru

Pete Guthrie · **Posted:** Thu Sep 16, 2010 10:01 am

how common is it, for a wrx to spin bearings using mobil 1 synthetic oil? i drive rather normally on the street in mine. Though i do use mobil 1. I found someone on nasioc who had spun a bearing on mobil 1, and want to know how common is this?

JamesShort · **Posted:** Thu Sep 16, 2010 10:19 am

M1 5w30 10w30 are very thin 30 weights. In a turbo engine, they will shear down into 20 weight range relatively quickly because they don't have very high HTHS viscosity (only ACEA A1 certified). Not to mention that boxer engines have different crank bearing stresses than Vs or inlines making a robust lubricant even more important.

So yes those particular grades of M1 are particularly bad for a turbo subaru.

However, not all M1 is the same. M1 0w40 and M1 5w30 ESP are both nice and thick (the former being a thin 40 weight and the latter being a thick 30 weight) that are ACEA A3 rated with HTHS of 3.5 or higher.

There are tons of spun bearings in WRXes on the net. Seems a disproportionately larger number of them are running M1 5w30 or Royal Craple 5w30.

JamesShort · **Posted:** Thu Sep 16, 2010 11:25 am

I suppose it would only make sense for me to offer alternatives.

The two M1 grades I mentioned would be very good.

Also Castrol 0W30 (german grade) is a very thick (12.1cSt at 100degC) 30weight and is the only Syntec grade that is all PAO/POE (group 4/group 5) based. It is ACEA A3 certified and has very good shear resistance in our engines (low NOACK volatility so will keep the PVC system clean).

The diesel oils turbo subbies run are also good choices: Rotella 5w40 synthetic or Rotella semi-syn 10w30. M1 Turbo Diesel Truck (TDT) 5w40 is a good choice as well. Keep in mind that if you burn a lot of oil, you might want to stay away from API SL oils given they are hard on catalytic converters when consumed.

TomFreeman · **Posted:** Thu Sep 16, 2010 1:22 pm

Ummm, read BITOG much James?

Pete Guthrie · **Posted:** Thu Sep 16, 2010 1:41 pm

what is 5w30esp what is that stuff? I am scooby newbie. and am not ready for a engine rebuild.

JamesShort · **Posted:** Thu Sep 16, 2010 1:51 pm

Pete Guthrie wrote:

what is 5w30esp what is that stuff? I am scooby newbie. and am not ready for a engine rebuild.

ESP is exhaust system protection.

Honestly I could careless about that. The fact remains is that is is a nice viscous 30 weight (over 12 cSt) with ACEA A3 certs, high HTHS viscosity, and decent shear stability.

TomFreeman · **Posted:** Thu Sep 16, 2010 1:56 pm

Realized post above might have sounded a bit sarcastic...not my intention. It was more meant to be a "Nice technical post" statement.

BITOG is an awesome resource. It's lead to quite a few of us running Shell Rotella T in gasoline engines.

Stephen Westerfield · **Posted:** Thu Sep 16, 2010 2:14 pm

TomFreeman wrote:

BITOG is an awesome resource. It's lead to quite a few of us running Shell Rotella T in gasoline engines.

Count me in that group. It helps that it's on the cheaper side of Synthetics too.

Vincent Keene · **Posted:** Thu Sep 16, 2010 2:31 pm

Stephen Westerfield wrote:

TomFreeman wrote:

BITOG is an awesome resource. It's lead to quite a few of us running Shell Rotella T in gasoline engines.

Count me in that group. It helps that it's on the cheaper side of Synthetics too.

Ditto, but when I started using the Rotella T-Syn is was about $6 cheaper per gallon than M1 and now the gap is only $2.50.

JamesShort · **Posted:** Thu Sep 16, 2010 3:10 pm

TomFreeman wrote:

Realized post above might have sounded a bit sarcastic...not my intention. It was more meant to be a "Nice technical post" statement.

BITOG is an awesome resource. It's lead to quite a few of us running Shell Rotella T in gasoline engines.

No worries, I didn't take it the wrong way. I've actually warned a few people like Matt McGrain or Steve Carter to stay far from BITOG......wifes might be pissed when you spend hours reading about F-ing oil and buying 35 qts (or seven 5+ qt jugs) of oil at a time (along with cases of filters) which take up a ton of space in the garage. All in a days work

.

Kevin Allen · **Joined:** Thu Aug 28, 2003 6:42 pm **Posts:** 3479

I use Valvoline regular oil, 5w30, and have been for 13 Subarus. Sometimes I use something else, if it's on sale with the Purolator filter. Pennzoil, etc.

Used Mobil 1 in a couple of RSes and the previous STi for a while, and noticed it burned faster. So I stopped using it.

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