Originally Posted by wtd
I say you would be fine sticking to what you have been doing. I don't run full synthetic in any of my vehicles including my newer 14 Mustang GT. Everything gets a blend.
I have a 98 chevy K1500 with the 5.7L that I bought new and except for a few years in the early 2000's,(Mobil 1 synthetic) I've always run a conventional or synthetic blend in it and at 138,000 miles, it still runs very strong with the same oil usage it's had since new.
Yeah, I don't use anything more than a blend. My Detroit 60 has 1,012,800 miles on it now using only a syn blend that is 75% Group II+ / 25% Group IV PAO. Motor is all original except for a water pump. Only uses about 1 quart of oil every 11-12,000 miles. Gets 22-23,000 mile oil changes, 50% longer than the OEM recommended interval. No HM type oil, no over the counter additives, just the same oil it has gotten since day one. About 30 used oil samples on it. Not convinced that a full synthetic would have been of any substantive benefit.
My wife's 2006 Cadillac CTS. GM says it needs M1 5w30. All it has gotten is Pennz YB conventional 10w30 which met the same GM6094M spec it required. Runs great and motor is all original. Just sold it this year to a neighbor who wanted to buy a nice car for their high schooler who was graduating. If it was in terrible shape I would have heard about it by now. The kid loves it. We had it garaged (heated in winter) when not being used. Nice tan leather interior.
