anthonyallred

Wondering about synthetic oil in an older motor. The engine has 300,000KM on it and The head gasket, rear main engine seal was done when engine swapped, and the oil pan has been re sealed. Would it be safe to switch to synthetic??? I head the only concern is that your old seals will start pissing synthetic if it has had regular its whole life?? Are there any other major seals I should worry about or should I go ahead and use syn?? Thanks

YotaFun

All I can say is search dude.
Its a wonderful button at the top of the bar there.
This topic has been discussed over and over on this forum.

PCE91V64x4

You can buy high-mileage synthetic as well as regular synthetic. Your call. Everyone has an opinion, but my next oil change will be with high mileage synthetic and Mobil 1 filter.

TNRabbit

there are two opposing schools of argument on this. Some have had bad luck with switching, but I've switched with SEVERAL high mileage vehicles and never had a problem. If the seals are questionable, you could induce leaks because the synthetic WILL loosen old sludge, etc., possibly opening up a path for oil to flow out.

mtrdrms

Ive never had a problem with the switch. High mileage, low mileage it doesnt matter. People used to scared of switching back to petroleum based oils from sythetic because of the swelling agents in the synthetic but no longer. I would run synthetic in my lawn mower if I had a good one.

Andy

Flash319

I am with Andy. I have never had a problem and Do run synthetic in my lawnmower.

TNRabbit

me,too:

Squeebs

Synthetic rules.

surf4runner

if it leaks, switch back...