Valvoline MaxLife in '97 grand cherokee ; 5.2 v8

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Jun 5, 2010
Got a debate going in my head as to which V:ML to use in my 5.2 with 212k miles: ML ful Syn 5w30 or syn blend 10w40

10w40 blend seems logical, but I have 5 qts of full syn 5w30 on hand that might be nice to use to clean stuff up inside the magnum block.

No need to use anything thicker than the 5w30 in that Jeep even in the south. It's already a high mileage formulation, good stuff.

If you already had it on hand, sure use it up but don't go out of your way to choose the 10w40.
Jeeps seem to like Maxlife. I'd personally put 10w40 Maxlife blend in it now and save the 5w30 for your next OCI when it will be colder. Both the syn-blend and full syn Maxlife are very high in detergents/dispersants, you'll not gain any "extra" cleaning from the full syn either, so again I'd use the red bottle blend now.
Bringing this back from the dead as I recently picked up a 1998 5.9 Grand Cherokee. The 97 5.2 that I had when I started this thing turned out to be a dud. Ditched it as part of a down payment on a 2009 Toyota Matrix 1.8L. Huge difference in every aspect lol

Fast forward to know, I picked up a very well maintained 5.9 Grand with 272k miles on it. Drove it from Texas to Florida without a single hiccup.

Going to change the oil to Valvoline ML 10w30 with a Fram Ultra Synthetic filter, and also give the niner a tuneup with spark plug one degree colder to resist detonation.

Before I change the oil, I want to do a piston soak. Already did Seafoam just to see what would blow out, and nothing came out. So this Jeep is in good shape for sure.
Besides, in the USA "synthetic" can mean highly refined dino oil, so what's the real difference...

I'd go with what's on hand and see how it goes, adjust from there
The roller cam 5.2 works just fine on any modern
10W30 or 5W30. 40 grade isn't needed but if you got it run it. It isn't going to hurt it. Plenty of high mileage state trucks run on 15W40 since new.
switched my sons truck to T6 rotella and it has been a happy camper even in winter starting up north in wisconsin at school
it's a 94 5.2 L 318
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