Newer vehicles largely come from the factory specifying synthetic oil. In the past I tried it in some older cars ( a Mercedes diesel and Ford V8 truck) with unpleasant results. Leaks everywhere. Including the rear end using 90wt Synthetic.

In a 94 Camry V-6, would it help with gas mileage? Would I have problems as I did in the past? The claim is that synthetics offer reduced friction given the same viscosity as a petroleum product.

I'm becoming a 'tweaker' in my advanced years.

 

It seems like a lot of people have stories about switching to synthetic at high miles and developing lots of leaks in a variety of vehicles (like https://www.camryforums.com/forum/ge...nthetic-38200/ for example). And there are people who make the switch and nothing bad happens (Synthetic Oil over 150k? [Archive] - Toyota Nation Forum : Toyota Car and Truck Forums).

If you don't mind closely monitoring your vehicle and don't plan to take it on any long trips (i.e. wouldn't need to get it towed far if something went really wrong), then switching to synthetic is probably fine. Also remember that synthetic doesn't "create" the leaks; it cleanses older sludge that is plugging those leaks.

As for gas mileage: Yes, switching to synthetic should theoretically slightly help gas mileage if everything else is in great working order. Toyota uses synthetic in their newer cars for this very reason.

 

I concur.

You will get some slight MPG increase but not much.

Synthetics offer superior lubrication and stability, this would be the main reason to switch.

Toyota has extending their oil recommended change interval periods for new cars as a result of switching to synthetics.

 

Well, I guess it isn't worth taking a chance. For years I resisted the ads for "Slick 50".

And I don't believe Sandy, the chunky girl who advertises for the "Lap Band" on TV. Too bad.