Synthetic oil?

I'm using full synthetic in my car. The general issue is if your car is already leaking, synthetic, being more slippery, will make your engine leak faster or more.

Synthetic is more expensive, but theoretically, you don't need to change your oil as often. So overall cost should be about the same. Unless, of course, you do buy into the marketing and change your oil more often than necessary.

The benefit is if you are storing your car, especially through the winter, the oil will not break down as easily. Also viscosity appears to be more consistant so simply starting it up and running is fine. No long warm-up period required.   That's why most new cars have no recommendation for warm-up periods.

The downside, besides expense, is most people don't really know the very longterm effects of synthetic oil on your car. If I only change my oil once a year instead of twice a year, does that affect my overall engine longevity? The jury is still out on that. If you only keep your car a few years and then trade it in, it doesn't matter.   But on 25+ year old unrestored engines (of which most of those years it's already been running on dino oil) the benefit of switching to synthetic in a daily driver is really an unknown and probably an unnecessary exercise.

Just my opinion.

Okay gentlemen...let's keep the debate going ...what is your favourite motor oil brand and why?

Royal Purple.

Because it makes checking the dipstick fun and exciting! And because I get it for pennies on the dollar when it normally costs a first-born child.

Huh, never knew GM had a re-branded Castrol. I just assumed they had some cheap AC Delco knock off, as I know Ford has a Motocraft brand oil. Castrol's pretty good stuff though, I know Mopar use them as well.