Over heating 40 (1 Viewer)

[efmb15cmb]

My 1979 40 runs perfect temper on surface streets for hours. But after a few miles on the freeway at 50 to 55 the temp gage goes all to hot. I get off and take surface streets again it cools down and runs at normal temp again. I have replaced the radiator, thermostat, and flushed the system. Any other suggestions?

 

[cooksflips]

My 1979 40 runs perfect temper on surface streets for hours. But after a few miles on the freeway at 50 to 55 the temp gage goes all to hot. I get off and take surface streets again it cools down and runs at normal temp again. I have replaced the radiator, thermostat, and flushed the system. Any other suggestion

My 1979 40 runs perfect temper on surface streets for hours. But after a few miles on the freeway at 50 to 55 the temp gage goes all to hot. I get off and take surface streets again it cools down and runs at normal temp again. I have replaced the radiator, thermostat, and flushed the system. Any other suggestions?

I would try a new water pump. I had an overheating issue after installing MINI truck PS and was loosing vapor at the PS mount on the head. My mount was not seating properly with the head bolts. I cut a new mount which sealed much better and replaced the H20 pump. with the new pump the 2f runs very,very cool. takes it about 30 minutes to get to operating temp it seems like. hope this helps.. have you checked to see if your loosing any antifreeze ? do you possibly have a air trapped in your system? Cut your heat on make sure fluid is plumbed all through the system and through the heaters.

 

[ceylonfj40nut]

Check you thermostat and fan clutch. I have had a similar issue when the belts are loose. Check those as well. Is your timing spec or advanced? Sometimes advanced timing causes overheating.