I have a 312 with 454 Mags. What is the safe oil temp range for them? I was cruising at 4,900 rpms and the oil temp kept rising and went past 230. I slowed to a 3,500 and they settled back down fast. The water temps were below 180.

You must have a blocked coolers- back flush them. BTW 4900 is not cruising- that is close to WOT. Max rpms I believe is 5000- 5400 range. Over 230 is getting up there.

Wannabe

The Full Throttle RPM Range of stock 454MAG's is 4600-5000, so I agree that 4900 is not cruising, that's about WOT.

230 is getting pretty hot. I don't like to see anything above 220, with 200-210 being ideal - Hot enough to boil away any trapped moisture, but still within safe territory.

230º is fine for oil. You want to see 210º - 220º all the time anyway to keep condensation from building up in the oil. 10º additional isnt going to hurt anything. I wish mine ran at 230º oil temps at WOT.

Now if it was 280º that is getting pretty hot but still acceptable for short WOT bursts with good modern oils.

You are 100% correct...

But I don't bother trying to convince anyone around here of that.

your right on with that statement dude.mine runs 240 all the time and when i run her hard 250.it has been this way since i owned the boat.same motor for 6+years.i do use synthic oil.it keeps its color longer and withstands higer temps longer.

230 is great for oil!!!!! Get that water out of that oil nice!!!!!

First of all, oil temp is very important as well as to what oil you run. Yes some synthic oil does all a lower temp but AMSOIL will run even cooler. It is a proven fact that AMSOIL not only runs cooler but with less wear & tear on the engine. Just ask Bob Tegue. Mercury Racing division is always blown away with the lack of bluing on the internal engine parts. If interested in amsoil, email me at [email protected]... Buy at dealer price..

Thanks for the responses... Yes, I used the wrong term... 4,900 was WOT not cruising. I have been cruising at 3,500 and am seeing speeds about 40 MPH.

So... it seems that there are two opinions here. 1) 230 is too hot and 2) 230 is perfect. What would Merc say?

If I use synthetic, what is the recommendation for weight and brand?

I have been working on getting my oil temp up. Had way to much water under valve covers. Oil was only get like 200deg not good. Now I am 220-240 and she is very very happy!!!!! Running brad pinn oil.

Skydog