97 Mustang oil question

[MustangGT]

Owner's manual says 5W-30, is it safe to run 10W-30? I've got an extra case of castrol 10W-30 from another car and wondering if I could run it a 1997 Mustang with the 4.6 V8. Thanks

 

[Patman]

Most definitely safe to run! A friend of mine bought a 96GT brand new and ran nothing but Mobil 1 10w30 in it, even after he put on a Vortech blower. He just sold that car and bought a rare Pacific Green 97 Cobra vert, and runs 10w30 Mobil 1 in that one too. IMO, 5w30 oil has no business in a high performance engine, 10w30 is the better choice. It won't thin out as easily as 5w30 does.

 

[MustangGT]

Thanks Patman, I'll go ahead and run the 10W-30 in the Mustang. Why does ford recommend 5W-30 anyways? Is it because of gas mileage? THanks

 

[Patman]

Yep! 5w30 is simply for gas mileage. If you look at the oil recommendations in other parts of the world that don't worry about gas mileage, they rarely recommend 5w30, even on the exact same engines sold in North America.