Opinions Please !!!!!

[bob gronotte]

I just purchased a new Z1 and the owners manual calls for NO muligrade oils. They say use straight 30W or 40W depending on the temp. Anyone have any thoughts. it's a 5.7 325hp
Thanks for the input, break in is over, time to do the first service.
Bob

[Timmy!]

I think my dealer puts 25w40 in the Marine Power engines.

[turbonine]

Is it a Marine Power? If so I thought all MP used 10W-30.

[gman]

Timmy, my manual says the same thing, not to use multi viscosity oil and then it goes on to say that 20w50 is o.k. I have a 5.7l 2005 MP engine. What year is your manual?

[Timmy!]

Is it a Marine Power? If so I thought all MP used 10W-30.

I bought 10W-30 for mine based on responses here and wasn't able to get it to drain from the drain hose so I took my boat and the oil to the dealer. They told me that they use 25W-40 (maybe it was 20W-50) instead because you don't want the light viscosity just in case you get into those higher rpm's while the engine is cold. I don't know if it's true or not.

[turbonine]

I think a few people in here who no more about engines than I do, may say that as long as it is 30 or 40 weight it doesn't matter if it is 5W/10W/15W/20W. All that states is its ability to flow at colder temps.

I use 15W-40(in my Indmar) which is diesel oil. Supposedly the rational is that the added detergents help.

I am just always careful to get to operating temp before throttling up above 1000 RPMs

[chpthril]

straight 30 or 40 is ok, or 15w-40 or 25w-40 is ok. I use the multi, as we run year round.

[SPBFAN]

I use Mobile 1 10W40 in the winter and 15W50 in the summer since the summers average temp where I live is 105 or greater. I am with CHP 10W40 would work fine. I recommend a known brand like Mobile 1 or Castrol. Just my preference.

[chpthril]

The only thing I would add, is difference between "auto" grade and "marine" grade oil. Although there is virtually no difference between the two's lubricating properties, the marine grade has more moisture inhibiting additives. This helps to keep the water suspended in the oil and prevent mixing (no chocolate milkshake) If you dont run the boat alot, the can be a plus. If you boat/live in a very humid climate, this is a benefit.

If you use auto grade oil, you may want to consider shortening the number of hrs between changes.

[bob gronotte]

Thanks for the advice. Being a long time auto and truck shop owner that threw me off. I even put multi in the Harley!