BlitzK5 said:
Is there any problem with switching back from another. My 454 had conventional in it when I first bought it, then I switch to synthetic and now im thinking about going back to conventional. Would there be any problems doing this?. I herd once you go to synthetic you have to stay with it. Is this true?
I've heard this but haven't ever been given a good reason why. I don't believe there's any problem with switching back and forth, although, I gotta ask, why would you switch back to conventional?? Synthetics lube way better. In my old 305 that originally came in my K5, I felt an immediate "seat of the pants" increase in the low-speed torque after switching to synthetic. The oil pressure went up by about 15-20psi as well.
It's a little more expensive for sure, but if you added up the increased cost of all your oil changes, it'd still be way cheaper than an engine rebuild (assuming that the engine wasn't worn out or damaged before the switch to synthetic, and is properly maintained).
The biggest complaint I've heard about synthetic oil is that it "causes oil leaks" which is completely untrue. Synthetics sure do clean the crud out of your engine though, and if you had an unknown leak that was being plugged with old, burnt, and thickened conventional oil, then the synthetic will clean out the clog, thus exposing the leak.
FWIW, when the mechanic pulled the 305 to install the 350, he popped the valve covers off the 305 to inspect it. He said "you gotta see this". The 305 with 150k miles on it had ZERO sludge in the heads. The synthetic had cleaned it out so well that the valvetrain looked brand new.
I was sold on synthetic from that point forward. It's all I use.
