Mark99GT

Anyone run 20w50 oil in the summer? The guy at napa tried to convince me to get 20w50 instead of the 10w30 (royal purple). Anybody ever run that weight before?

VARifleman

Your car requires 5w20 all year round unless you've changed the motor.

NightmareStang

I'd say go with the 20w50. In the summer that 5w30 gets like water in really hot summers. But for winter go 5w30.

beheivjer

15w40 rp is the heaviest i would ever put in anything i drive

VARifleman

Because Ford doesn't know simple things like what the best oil to use in their very low tolerance engine...

mustangGTdude1031

I have Royal Purple in my car and its great!

silver03gt

Old school motors, putting 20/50 in is all good, but these new motors require the lighter wieght oil because of the extremely tight tolerances. I wouldn't run any higher than maybe a 10/30-10/40,,,, I personally stick with the 5/20

NightmareStang22

Sorry, the old school info kicking in. Maybe thast what the tech guy is thinking as well.

SikGT

A Tech at Super Autobacs said that 10W30 Royal Purple is one of the best for protection especially if you haven't done anything to your car.