ok i have an 88 f150 wht a 302, 220000 on the original everything. now im thinking about switching over to valvoline fully syn. 10-40 or syn blend w/e it is. now i know i can do that without a problem biut the question is, at work a coworker of mine says that diesel oil is better for a motor, i thought that it had a higher heat breakdown or w/e but he claims it has more cleaning detergents in it and will run better. any truth to this, cause i work at advance and get get mobil 1 diesel 15-40 fully synthetic. but i need a couple more opinions be4 i put big rig oil in it. and btw forget my last post about the capacitor and resistor thing, ill find the exact name of it later

 

Bump

 

Gas engines do not generate the carbon waste that diesels produce, so oil designed for diesel engines must have more soap-like additives to attract the carbon waste. They also don't operate at the RPM's of gas engines, so they can be a little thicker. If you run a diesel engine with a fresh oil change for a day, the oil will be as dark as midnight, it will still be good oil, it just has a lot of carbon in suspension. Gas engines also produce carbon, only it takes 3 or 4 thousand miles to be noticed. Will it hurt anything by running it? Probably not. I would imagine its thicker, so you might want to run a lower weight oil.

 

Chevron Delvac 10w-40 is excellent oil. It posses the correct and neessary boron and zinc properties to assist a higher mileage engine is retaining as much efficiency as it can possibly put out.

Do I think you will notice an improvement in efficiency? no, most likely not.
Do I think running Delvac is good for the internal? yes.

That being said, any good quality oil is better than sludge and cheap ****.

 

I would steer clear of synthetic in such a high miles engine. I did it once on another pickup and the synthetic oil oozed out through the gaskets because it was so thin. I would stick with regular oil or those made for high mileage engines.