I'd be inclined to go with the GTX. Quite a few people have had good remarks for it's additive package. Valvoline on the other hand seems to have a weak additive package.
Valvoline is made right here at Ashland Chemical.
A subsidiary of Valvoline.
The factory's name may not say valvoline (actually it does on their website) but that's what they make and I dont think they make anything else.
I prefer the Valvoline, but I run no less than Maxlife or Durablend - there is no savings in buying the all climate moneywise ($0.30/qt?) so its worth it to me to go with a blend.
So?...There are a few large refiners of base oils. There are a few makers of additives for the oils (Lubrizol, ChevronOronite,...who else?). There are many oil blenders with their own staffs of chemists and other experts who put these oils together, then their marketing departments tell them, in effect, what quality product to put out by dictating the price point of the oil.
By your thinking, is ChevronTexaco necessarily superior to almost all others because they produce all their products' ingredients? (And Chevron makes good stuff, but better than most the others?...I'm not sure.)
Castrol is one of BP's brands, and BP is one of the world's oil giants. If BP produces base oils in other parts of the world but buys base oils in the U.S., is that good or bad, or makes no different? Who in the world knows more about oils than BP?
palmerwnd, I had always thought that Valvoline All-Climate was refined by Ashland ... but evidently most (all?) is actually bought from Petro Canada or another concern. Ashland must use their refineries for other products.
Ken2, we all pretty agree that every major brand is at least decent. So, my bias towards producers that make their own is showing here. I didn't tell Tommy to pick another brand but I just don't think there's much of a difference between the two for the reasons I cited.
Also, the ink on the BP- Castrol deal is still fairly fresh. It may take several years to fully integrate production of all products.
GTX anyday over Valoline including MaxLife vs GTX high mileage I used to use MaxLife until I saw GTX high mileage then switched over. Right after that, I found out from this board MaxLife doesn't have as good of additive package as it used to.