Engine Overheating Issue found

[dwna1a]

We all do it, we forget or we are just happy an issue is fixed. This time I didn’t forget! I knew I had an issue, I thought it was my circulation pump or a bad thermostat, I just knew I had a blockage somewhere.

It took heat and a big impact to get this off, you can’t see or notice a blockage. Pulled the base and found this issue. You can see the buildup inside the hose barb threads. Now the fitting had to be drilled and then cleaned out. It’s back in the new housing.

Moral of this repair, you must look, pull the hoses check for any blockage. Look into the fittings. I back flushed the water heater hoses and found more crap in there. My next cooling maintenance will be an antifreeze change. Please remember mine are 1988 FWC Merc 350’s I do still use the water heater as a heat exchange.

 

[dwna1a]

Let me ask a question to FWC folks that still use the water heater as a heat exchanger. The helm side thermostat was just as pretty as it was 6 years ago, so is this issue from using the water heater system?

 

[dwna1a]

PD, thank you! You kinda made me start chasing the real issue down

 

[PlayDate]

That looks like coolant scale. Calcium and magnesium have the tendency to combine with the phosphates found in old-fashioned antifreeze. They form calcium and magnesium phosphate scale on heat transfer surfaces and wreak havoc.

Glad you found it.....September seems to be our best CSR month yet for solving over temp problems.

I believe the difference between the two engines is probably more of a factor of the antifreeze itself over time. 35 years of operating probably had multiple anti freeze changes and probably little or no flushing.

I'm guilty of it too. I seem to only do it when I am changing something rather than on a real schedule.

I do have a tester to check the freeze condition of the antifreeze which is a pretty good indicator of its effectiveness. Once it starts to breakdown....bad things happen.