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Miss Rita
09-18-2011, 10:26 AM
Time to winterize the boats soon. Recently I've been using Rotella 15W-40. O'Reilly's has Chevron Delo (probably equivalent to Rotella) on sale, $13/gallon. The problem is that I'll need five quarts of oil, and have some Rotella left over.

Question: Is there anything wrong with mixing oil brands? If one oil is deficient in one way or another, wouldn't adding a second brand may make up for it.? It follows the philosophy of not putting all your eggs in one basket.

Thrall
09-18-2011, 12:01 PM
It won't hurt anything to mix the 2 brands of oil.
Not sure what boat you have, but the boats after 01? maybe reccomend 15W40 in the trans and 2 gal is just about right for engine and trans oil change.
BTW, Oreillys had Delo for $10/gal back in july. Bought about 20gal. Got enough for the truck, boat, mowers, etc for the next few years!

east tx skier
09-18-2011, 05:27 PM
Because you have a 351 and a flat tappet, I'd suggest finding 5 qts of Delo, which last time I checked had the recommended levels of ZDDP, which Rotella no longer has.

JMann
09-18-2011, 05:50 PM
I use Castrol 10 40 in mine with a ZDDP additive to make up for the missing ZDDP in todays oils. I have done this for 2 years now with no problems.

Miss Rita
09-18-2011, 10:47 PM
Because you have a 351 and a flat tappet, I'd suggest finding 5 qts of Delo, which last time I checked had the recommended levels of ZDDP, which Rotella no longer has.

Advice well taken; thanks!

Would that also be best for my 1991 MerCruiser, with the GM 5.7 liter?

east tx skier
09-18-2011, 10:54 PM
Advice well taken; thanks!

Would that also be best for my 1991 MerCruiser, with a GM 5.7 liter?

Probably. I think, but don't know for sure that they did not have roller cams in the GM engines until they started up with the Vortec heads. The short answer is ... flat tappet cam --- need Zinc.