Not according to Eddie, Gellner, Ilmor and others I have talked to... all read AFTER cooler... I think they know a few things about marine engines..

Ok, you keep doing what your doing.

Come on, some reality has to come into play. Agree seeing what goes into the bearings is good to know, but if a great fitted cooler lowers the oil by 50 degrees, I wonder what a not so great cooler does? I had a 12x2 on the motor, and now I have a 18x2 and I'm hitting 270+ degrees. Sure wonder how hot the oil was getting with only a 12x2 cooler was doing because I was not letting off the throttle, because at the time I didn't know there was a problem? Include stock oil lines and fittings prior and who knows what was happening to the motor.

I will, been for 12 years with ZERO oiling issues... just sharing advice from the pros that I was advised....

BTW, Mercruiser reads AFTER COOLER ALSO... they would know nothing I assume... carry on.

I started with 2x18 and -12 lines and didn't like how hot it got even with 500hp and then went to a 3x18 with a thermostat that was a bitc* to plumb while in the boat. I wish I did it that way from scratch.

If you read at the pan, you have no idea what what your temps are feeding the bearings or any clue what your cooked temp is... that's why you read after....

I am looking into a high oil temp reading now myself. If I traced it out correctly, my Mercruiser is reading the temperature coming out of the block into the filter. From the filter, it goes into the cooler and out back into the block. Am I wrong?

We've been debating this before or after the cooler sensor placement for years here. My take on it is, it's good either way. Why? Because it means we are all watching our oil temps and adding larger coolers if things are getting into the cook zone! We're not being oblivious to what's going on inside the engine either way.

On my last boat with built engine, I had only one oil temp gauge, but installed 3 pole switch, and two sensors. One pre-cooler, one after. All I had to do was flip a toggle to see the temperature drop of the cooler.