M1 0w-40 for Subaru WRX? Too Thin?

[Hamilton]

I cannot find GC in my area, but I did find m1 0w-40. But should I be worried that it is a 0w? I didnt know if this would cause more wear when the car is starting up cold than a 5w or 10w.

Thanks

 

[mcrn]

No that means it will flow easier in the cold. Its not thinner at cold than it is when its hot.

 

[JohnBrowning]

I would not worry too much about it. I would do a UOA though to see how it does. It has been my observation that M1 0W40 either does a great job or a fair job in an engine. If your engine likes it then that is another choice you will have when GC 0W30 is out of stock. The M1 0W40 is designed to shear initialy then thicken up as the OCI is extended. In some car's the shearing effect seems to produce lack luster wear numbers but other car's it seems to have no effect on. It has great TBN retension. It has great cold cranking performance. I usualy think of the 0W40 the same way I would a 0W30 because almost all 0W40's shear down to a 0W30. In my Toyota M1 0W40 did a good job dureing a 6 month run wich included winter.

 

[Titan]

Since that engine is spec'd for a 30 weight, I don't see how you could think it was too thin. Some people are running 5-20 in Subaru engines and getting very nice UOA's. Being a WRX, I don't know that I'd try it, but, any good SM 5-30 should do fine...these engines aren't that hard on oil.

 

[Gene K]

To oversimplify the W rating is how well the oil pumps at low temps. Its not a viscosity.

A 0W-40 is simply a oil that is the same approximate viscosity at 212*F as 10W-40 yet pumps better at low temps.

How could making your engine only wait 5 seconds instead of 10 seconds for oil pressure at Subzero temps harm it?

 

[buster]

No it's not too thin but expect it to shear....

 

[double vanos]

Is this another one of Mobil 1 oils that is now a GRP III? I used to use it in my Bimmer until I discovered GC.

 

[bluesubie]

Quote:

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Since that engine is spec'd for a 30 weight, I don't see how you could think it was too thin. Some people are running 5-20 in Subaru engines and getting very nice UOA's. Being a WRX, I don't know that I'd try it, but, any good SM 5-30 should do fine...these engines aren't that hard on oil.

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Spec'd for a 30 weight, but 40 weights are also spec'd in higher temps (as you may know). The 2.5 turbo's do seem a little harder on oil but I don't know what year the OP's WRX is (2.0 or 2.5).

A 2.5 Forester XT owner on subaruforester.org that runs M1 40 weight always ends up with a 30 weight living in FL. His OCI's aren't that long so it would probably thicken back up like John Browning said.

-Dennis

-Dennis

 

[buster]

Quote:

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Is this another one of Mobil 1 oils that is now a GRP III? I used to use it in my Bimmer until I discovered GC.

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No, I think this one is all PAO + AN.

 

[JohnBrowning]

I am agree with buster M1 0W40 is not GIII!

 

[goodvibes]

My suspicion also.

 

[BrianWC]

Well, it's the only Mobil1 viscosity the website recommends for my SAAB 9-5... I guess b/c it's their only oil in the 30-40 weight range that is A3-A4....

 

[Turbodriven]

I have a mate who has a Possum Bourne (spelling) built Rally spec Sti and he runs Mobil 1 in it. He drives the car like a monkey and the oil has held up well thus far.

Im pretty sure it will work well for you.
Having said all that, Scoobies love Motul 300v, so if you can get that oil, you be better off...but not by much.