I actually asked the local dealer today, while dropping my car off for electrical problem, about using synthetic. Service advisor informed me that Ford will void warranty for the engine if I did that. Although he did recommend to use the semisynth stuff so go figure.
I understang in foreign cars they prefer synthetic because of close telerences. In our big blocks, not an issue and regular thicker oil work out better to provide tighter seal.

 

Your service advisor in my opinion is full of hooey. I've had the dealer put in synthetic and they didn't say a thing. I asked the Ford mechanic when I bought the car and they said it's no problem to put synthetic oil in it just keep with it.

 

hmm, this service advisor seemed pretty upset when I asked him, its like I am some kind of moran for not Knowing it.
I did some research and realize that Synthetic is not recommended in older big block engines but for our new 4.0's I guess it wouldn't hurt. I don't think I'll share that with my dealer though :-)

 

I concur about the service advisor, full of HOOEY (?). I believe MOTORCRAFT offers a synthetic oil (or is it a blend?). I think a car owner has to get pretty radical with a car before you can void a warranty.

 

best thing to do is to not say anything if any problems come up :-)

 

synthetic flows better at colder temps at startup, it circulates faster at startup which is the most stressfull time on a motor besides redline. all new mercedes use mobil 1 with a recommended change at 10 to 15000 miles . a nyc taxi cab test was done a few years ago between syn. and reg. oil . they took the motors apart and the bearing wear differences were about the same but they noted that the cabs are never shut down so there is very few cold starts . So if you live in a cold region (north) synthetic is the way to go .

 

I have always used Mobil 1 in all my cars , that service advisor should be fired for a stupid comment like "you will void your warranty .." that is ridiculous,lol. I hate dumb asses that work at ford dealers and think that every client is automotively retarded.

 

awwww now why do you gotta go beating up a corvette like that haha

 

Thats what my other car is for,je je, beating on Vettes and Crapmaros

 

Haha ok