Colorado_Mustang

The only thing that happens when you go from synthetic to conventional is a loss of performance, more oil consumption due to boil off, and a loss of protection due to inferior oil quality.

|MusTang

I know for a fact that constructor say not to put synthetic oil for the break in so that everything can wear in(seat) properly.
and from what i know before you could not mix sull synthetic and regular oil because of the coonstitution of the oil or something like that.but with a blend you could.true??i dont know.but i think that now if you ran out of synth oil and you need to fill in,you can use regular oil.
and for old engine,if you switch to full synthetic,since the engine wear is bigger than a newer engine,you would just use more oil.but that can probably can be fixed by using a higher grade.
if you use a blend or even full suynth you can switch ouil with no problem.

suzukidragracer

Regular oil makes the gaskets swell, preventing leaks. Some of the first synthetics didn't do this, so leaks occurred more frequently.

Almost all synthetics nowadays swell the gaskets so you shouldn't have anything to worry about.

prochargedGT

it is just what they said back in the old days, you can switch back and forth all you want...synthetic oil just doesnt break down as fastly as conventional oil

mikemic

You can switch from conventional oil to synthetic and back if you like. Motorcraft synthetic blend is a great performing oil for the money.

jkm1987

i ran full synthetic mobil 1 for a year and a half was low on money and put synthetic blend the only difference was that i got a little better milelage out of the synthetic so im going back to it i dont know why it got better mileage but it did i went from about 17-18 city to 14-15 city and my driving habits havent changed