wthalliii

I realize that this question has been debated before. The oil that Ford recommends for our GT's, 5W-20, just seems too light for the summer temperatures here in Texas. But when I read the comments in other threads about this, some people say that we really should trust Ford on this one. Other people say that Ford doesn't care how long our engines last, and it's better to use a heavier oil like 5W30. (Just to boil down the main two viewpoints.) So what kind of driver are you - mostly street or track? What kind of climate do you have where you are, and what weight of oil do you use?

Fourth Horseman

I'll be running synth blend 5w20 in my GT's engine until the 9000 mile change at which point I will switch over to Mobil 1 fully synthetic 5w30. This is the oil I've been running in my Marauder's 4v DOHC 4.6 V8 for nearly five years now. I know a lot of people scoff at synthetics, but I'm a believer.

ANBAUTO

Well i let ford do my first oil change just because it was free and now that i change my own oil i now use Valvoline SYN Power 5-30

I live 5 min from SF so our weather is always differnt from cold to warm weather.

RetroS197

I like the 5W20. What really Pissed[:@] me off was I thought it would be cool to change at 1000 miles just because of all the breakin so I went to my local garage and said I wanted 5W-20 SYNTHETIC!! About halfway through I walk in the garage and the mechanic is putting 10W-40 REGULAR!! He explained to me it wasn't a big deal, they said there was "NO SUCH THING AS 5W-20". So I kinda was worried, thenthe secretary beeotchwants toCHARGE ME FOR5W-20,because thats what I said. I said &*^%&^%(&^&amp^ NO!!! I had to argue with the manager so I could pay for 10W-40, whatTHEY PUT IN!!![:@] I will never go there again.
Anyway, I change my oil every 4-5000 miles because the book says that for Ford Cars and nothing diferent for mustangs. I also ALWAYS do it myself now, that garage has &*^&*ed me up so many times, I do my own rotations and everything.
What do you all think?

RetroS197

Sweet Maurader AND stang Man!! I love it, will you sell it?

cfr865

They haven't used 10-40 in cars for 20 yrs. I wouldn't take my lawn mower to that place.

Fourth Horseman

Thanks! No, not selling the Marauder. That car and I will be together until one or both of us end up at the bottom of a smoking crater.
With any luck I'll be ordering a Vortech supercharger kit for it this spring. *fingers crossed*

impaler

I'm definitely a street driver, it's my daily ride. I live in West Texas, actually, where it's super dusty. Still, I go with the 5,000 mile oil changes and use Mobil 1 5W-20. I'm no engineer, so I trust the engineers to steer me right. I don't believe that's naive, and it took me a LONG time to train myself out of the 3,000 mile mentality.

lteix

Just switched to Royal Purple Synthetic 5w-20 at 9,000 miles. Motocraft synth-blend at 3k intervals up till then. I plan on going at 5k intervals now. Love the RP....I can feel the difference. Just revs smoother. Freeway MPG is now up to 27 from 24-25. I find myself shifting at higher RPMs now so my city MPG actually went down.

extuner

Mobil 1, I live in Phoenix Arizona. Temps in the summer 110 plus are not uncommon. 10...30 for sure for here. I tried the 5-30 and lost a 1/2quart of oil every 3,000 mile oil change. Switched to 10-30 and I am a happy camper..no oil consumption now.