Synthetic oil question

[SaltineAmerican]

Mine is a 95 T4R with a rebuilt V6. The guy I bought it from was the 2nd owner and had the rebuild performed. He told me that the ONLY thing I should use is Mobil1 20w50. That doesn't sound right to me, I was thinking 5w30?

 

[02SE]

Well, Mobil doesn't make a 20w50 in their Mobil 1 formulation. They do make a Mobil 1 15w50 formulation, and it is a good oil. But it's a higher viscosity than you really need. In Houston you don't get really cold temperatures, so you can run it if you want, but it will negatively effect you fuel efficiency a bit.

If you want to know what Toyota recommended, looking at the Owner's Manual for the '93 3VZ-E powered truck I used to own, the recommended motor oil viscosity for ambient temperatures are as follows:

From 0 to 100+ °F 10w30
From 55 to below -20 °F 5w30