Engine oil choice

[Cooler]

Bought some Mercury brand 25W50 synthetic blend engine oil for oil change. The container says high performance marine applications. My thought is, if this is formulated for HP engines, it should be even more effective with my Crusader 5.7 XL, and offer a high degree of lubrication. I run the engines at 3000 to 3100 RPM most of the time. Talked to a Mercury "certified" mechanic about that oil. His reaction was he would not recommend using this product because it is formulated for Mercury Verado engines only. He said something about an "impact" performance condition, that may negatively affect my Crusaders. Guess I can still exchange for a better suited product, but not convinced I should. VIPER - what do you think? er

[Viper]

I wouldn't use that oil in your application, not only is it not designed for your engines, the cost is unnecessary. It's formulated for specific 4 stroke applications including racing and high horsepower engines. Verado is one of them but if he said "Verado only", that is incorrect.

[Cooler]

OK, thanks. Will try to exchange for a more standard formula. Is there any engine damage potential? ( just in case I can't exchange ). er

[Viper]

Really depends on what your engine calls for. If the requirements are close it's not that concerning, but if they are a couple of grades apart, that could be damaging as thicker oil doesn't flow as easily in an engine designed to use a thinner grade due to tighter tolerances. Depending on the engine, even at proper operating temps the thicker oil might not protect as well, will reduce engine efficiency, won't transfer as much heat (essential) which can lead to other issues, and reduces fuel economy.

[Gilligan 1955]

I just purchased a 89" 3807 with gas 454's. It was purchased from the owner of a Ford dealership. Why I'm saying this, is that he had access to some knowledge people about oil. When cleaning out a closet on the boat I found a half a dozen quarts of HD Diesel oil. When I asked him he said "that's the oil to use". Doesn't make sense to me. Thoughts?

[Midnightsun]

When I had gassers I always used Rotella T4 15w 40 which is a diesel oil. If you search various forums you will see there are several that swear by it. Heck, even used it in the PWC's.

[Viper]

I'm not a fan for gassers but that horse has been beaten to death!

[pepmyster]

QR_BBPOST When I had gassers I always used Rotella T4 15w 40 which is a diesel oil. If you search various forums you will see there are several that swear by it. Heck, even used it in the PWC's.

That's all I've been using for years in out Merc and VP 8.1's. Fantastic oil!

[KyleR]

If you're going with 15W 40, I have always used Valvoline Premium Blue. You can almost always find it on sale at NAPA for $16.99 - $17.99 per gallon. I chose it as is actually recommended by Cummins, but it's great for gassers too!

Kyle

[mjk1040]

Rotella use to have zinc in it, last rumor I heard they were cutting the zinc content. Before that I was told by a Rotella salesman thru a very reliable mechanic that the Tractor Supply oil was Rotella oil with Tractor Supply label? Now that its hard to find true "OIL" and everything is synthetic or a blend of oil and synthetic, it makes it difficult on what to use or not to use!