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Engine running to hot at 3000rpm

jeffsboat

Contributing Member
"I have two 1978 318 engines t

"I have two 1978 318 engines that have closed loop cooling. One engine is approaching 200 F at 3500 rpm. The other approaches 185 F at 3500 rpm. I will be pulling off cooling components this fall to try to find the restriction. Any suggestions on where to start? How do you test these components (transmission cooler, heat exchanger, pump, other)?

Thanks in advance for the help,
Jeff"
 
"I like to start with the simp

"I like to start with the simplest potential causes and work toward the more complex and expensive ones. Check the condition of the strainers (not clogged and no air leaks), impellers(remove and flex vanes to check for cracks), thermostats(boil in a pot of water to see at what temp it opens) and seacock/through hull intakes(no restrictions or partially closed gate valves). If those are all OK check the heat exchanger for obstructions or a collapsed intake hose."
 
"Bosco nailed it!

THe other


"Bosco nailed it!

THe other Jeff

PS: A tiny air leak BEFORE the raw water pump can cause massive overheating, so look careful there."
 
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