Carbed 454s with closed cooling - stbd motor overheats even at idle.Water goes through clean thru hull, clean raw water basket, to new impeller pump to trans oil cooler then oil cooler then to heat exchanger. Running antifreeze water through block and through Gil manifolds - raw water through top of exhaust only.

Heat exchangers serviced, removed thermos as prepping to add blowers, replaced block water circulators with marine bi-directional units, replaced impeller - back flushed and found broken blade and removed it. All belts tight and it is pumping water well .... so what have I missed?

Could second oil cooler be clogged and still have lots of raw water pumping through exhausts?

Could removing the thermos be a factor (other motor barely shows temp at idle without thermos - was going to go w none or 140s). It almost acts like there is a blockage in the block itself but backflushes do seem to do as expected water flow-wise in all directions.

Bit stumped.

Merry Xmas All!

I think that I would pull the new engine circulating pump apart and make sure it has an impeller on the shaft.

Lol

He prob was nt joking

I have been posting that the water circ pumps has had issues for years. The OEMs after the fact even put out SB s to the dealers but again it was after the fact..

SO that said which one did you buy and from whom ? If you bought one of those UNDER 100 buck water circ pumps good luck.

here if you think we are kidding.
The pump was still almost new. And there is other issues with them. If you need help with these let me know.

so what brand was that one?

if its using anti freeze could be a valve seat 2c

Did this issue just start?
What temp is getting to??
Does it keep climbing??
Is this in the water or on a hose??

Is it a mercruiser setup?