1991 4.3l omc cobra loosing coolant from somewhere

[ruggles]

Hi everyone. Had a pretty sucessful summer with the boat but after 2 weeks of tubing the boys etc the boat started to get hot while under load but would cool off at idle. I found my coolant level had gone down quite a bit. Must be a slow leak. Anyways there is nothing leaking externally. No water or coolant in the oil so am I correct I assuming it's probably in the heat exchanger?

Thanks
Ruggles

 

[Scott Danforth]

probably, or its a blown head gasket.

have your heat exchanger pressure tested, if that passes, pressure test the block

 

[ruggles]

I should say it cooled off fine once I topped it up. I would think if it was the head gasket i'd most likely have either coolant in the oil or a pressurized cooling system which I don't seem to have. thanks for the info

 

[Scott Danforth]

I should say it cooled off fine once I topped it up. I would think if it was the head gasket i'd most likely have either coolant in the oil or a pressurized cooling system which I don't seem to have. thanks for the info

not all the time, could simply be sucking out coolant slowly. hence the need to pressure test and find out exactly where the system breach is.

 

[ruggles]

Ok thanks for the info Scott. Hopefully I can get back to the boat in the next month or so to perform the pressure test. is there a DIY method?