Just installed a 2x18 on my mine and it will not keep it cool. Have 5/8 fittings and lines and reaching 260 to 270 when running hard for short time (Won't run it long until I get the temps down), running 240 for just cruising. Will be installing a larger one soon

you reading before or after cooler?

Before the cooler

I would read after, you wanna know whats feeding bearings... I see 15-160 average after cooler, 190-220 MAX after a hard run, that's about 50 degree drop (normal) oil in pan 230-270 is not horrible before cooler... if you see 200 after that's 250 in pan if cooler is dropping the 50 ish that it should.

I would like to know what the after the cooler temps are, but guessing any cooler drops 50 degrees might be stretching it a bit. Sure glad I decided to change lines and cooler from original build. Just think if it hits 270+ now, it was roasting the oil with only a 12x2 inch cooler on it originally. Soon as my gauge gets to 160 my oil pressure goes from 80+ to between 72 to 75 psi (I think all good), it stays steady until around 240. When oil temp gets above 240 the pressure starts dropping below 70 and at 270 it falls a tad below 65 and this is where I let off the throttle.

When going to idle at 260, pressure is around the 25 psi area. As motor cools it comes back up to 45 when below 220

When I get my next cooler I might get another sender to install after the cooler, so I can move the wire over to see what the difference is

Before cooler is best to watch, its the real temp of the oil, And do you really know if and when your in bypass?. Cooler all Junked up all of a sudden. For watching both, 2 senders 1 gauge and a switch works. and no finding room in the Dash Panel

Didn't think of that, should have, that would be so easy

all marine engine builders I ever talked to said 50 degree drop is what it should be if cooler is proper size, mine is right there.. I have measured at pan and cold side to see.

my oil pressure goes to 25-30 at idle after a decent run that's plenty, it's 70+ anything over 2000 rpm, I am a fan of high pressure and shunned oil pumps .

Per Eddie young: I read the temp going into the engine. If you read it before the cooler, You are taking the cooler out of the equation. If you have a small cooler, the temps will be higher than if you have a large cooler. I want to know what the bearings are seeing. I don't want to see over 230-235 deg. That would put it near 300 before the cooler. A conventional oil will start to break down at much over that.


i asked to verify my thought process when I was doing my own engines guys said I was doing it wrong, I went with Eddies and my best buds advice with this

You think the oil coming out of the cooler doesn't instantly get hotter going through the pump and running through the crank ? you want to read the hottest oil. plain and simple. then you know for sure.