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Using 0W40 instead of 0W20 oil on the 2013 2.5 OB

47917 Views 25 Replies 17 Participants Last post by  avenger09123
Hi friends,

Possibly a dumb question (as I for some reason cannot fully wrap my head around the oil viscosity thingy), but my 2013 2.5 Prem CVT manual recommends 0W20 synthetic oil. If I was to use Mobil 1's 0W40 oil instead, would it do any harm, either in short run and/or over time?

I currently have only a few hundred miles on my 2013 OB, but plan on doing first new car oil/filter change around 1000 mile mark.

plex :cool:
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I think there is more to it than just the pump having to work harder. It can only work so hard before the relief valve opens up. The oil galleries and bearing clearances may be smaller in this engine due to the lower viscosity oil. Some areas may not get sufficient quantities of oil. Why take a chance? T
I would like to think engine designers consider that at some eventual point – oil gets dirty (and is there forever).<O:p</O:p
Mobil 1 0W-40 Viscosity Index 185 / Mobil 1 0W-20 Viscosity Index 173.<O:p</O:p
Chemically, both oils exceed Very High VI (>110) classification. Mechanically, I doubt the 0-40 would fail lubricity performance, correlating the Forester-T runs Syn/5-30. Insert-Make-Here run 0-20 to hit better 40ºC/100ºC ASTM specs, CAFE as alluded to.<O:p</O:p
In (practical) application, it makes no (oil related probability) difference whether in–warranty/off-warranty, you either run spec/non-spec – get the 0-20 (especially if you DIY).
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