Synthetic oil changeover in high mileage engine

[NYrr496]

Synthetic oil isn't really synthetic at all. It's still oil. It's engineered so all of the molecules are exactly the same size and it has different additives than conventional oil.
My Yukon has 225,000 miles on it. I use Quaker State 10-30 and a Baldwin filter. I figure if it ain't broke, don't fix it.
On the other hand, I have absolutely no problem using synthetic gear oil, power steering fluid and trans fluid. I've actually seen a slight mileage gain.

 

[the99hoe]

I bought my hoe with 124 on the clock and i changed to synthetic, didnt do much and noticed more leaks. Like other before said it was already leaking there i just didnt notice it. If i was you i would buy a good conventional oil and just stay on top of the service intervals. Take the money you save on the oil and buy fuel filter and other things commonly overlooked or forgotten about. Thats what i would do but to each their own.

 

[John Redcorn]

I usually switch to mobil as soon as I buy something. The tahoe I didn't have much money when it was time for the first oil change but I put in mobil 0w30 last weekend.

My dad and I both use mobil 1 and do 10,000 mile oil changes, 5000 mile mobil filter changes. I've been doing it since I first started driving 16 years ago, him for 20ish. Between him me and mom we've had 10 various gm motors go close to or over 200k before they were wrecked or sold.

Only internal problems any of us have had was a broken rocker arm for me on a 2 month old 350 long block but the rockers I put on were 23 years old (it broke right after I showed a 66 289 mustang what's up) so....also, again for me, a stuck lifter on a 3.8 v6 but that was the result of the oil getting contaminated with antifreeze. once the leak was fixed some atf and an italian tune up fixed that right up.

I've been seeing a bit on the internet, mainly on subaru forums and hearing from my brother (who's a subaru driver) a bunch of good stuff about a new Rotella 5w40 sythetic. Some of the forum guys did oil analysis on rotella synth and mobil 1 both for 8000 miles and they showed rotella still had a lot more life left in it than the mobil did. My brothers wrx says mobil 1 5w30 right on the cap but he said the thicker 5w40 quieted down the idle lifter noise or whatever those crazy things have instead of lifters. (side to siders!)

 

[Vanilla_Gorilla312]

+1 on the Royal Purple