2005Stang

Just was wondering if anyone has used Rotella T6 5W-40 synthetic oil in their V6 Mustangs?

cruisin5268d

Why are you wanting to use that oil, in particular?

2005Stang

I received a couple gallons on the cheap and before I wanted to know if it would hurt the engine at all.

Bitter

I suspect you're more concerned about the weight than the brand. 5W-40 is heavier than what is recommended. I believe the recommended weight is 5W-20. Will it hurt it? Probably not, but that's a risk I wouldn't take simply because it was cheap.

cruisin5268d

The track pack GTs come with 5w50 and have the same engine as non track packs. So 5w40 is not going to hurt anything.

The decision to use 5w20 from the factor was influenced by a slight gain in fuel economy, amongst other reasons. Oil is heavily discussed here and I encourage you to do some searching and form your own opinion on the facts at hand.

2005Stang

My owners manual says 5w30, that why I was wondering if there is much difference from 30 to 40, yes I have been researching and still on the fence.

Goldenpony

It would probably be OK in the summer, but I wouldn't use it in cold weather. Just my $.02 worth. Personally, I use what the factory recommends.

Nuke

I'm with Goldenpony on this one. The OM calls for 5W-30 for the 4.0 and it's not a major change to use the next weight. But I, too, would be leary of it in cold weather, simply to be conservative.