The Stovebolt Site Forums The Shop Area Engine Shop runs hot when while driving

A good friend has a (lets say a truck). Not really but this is a general natured question. It runs hot while driving but will sit for an hour and run cool as can be. It has a standard fan and an electric fan that cuts on with the ac compressor. I told him to make sure his guys didn't put the regular fan on backwards. I figured that would fight the flow of air when you are moving but cool just fine stopped. Does anyone have any other suggestions. It has a manual transmission, a fresh rebuild on the motor and trans, new radiator core and hoses. Thew added the ac and it was running while the (truck) was sitting running in the shop.

Thanks for any hellp
Neil

re check hoses could be defect from factory and be collapsing while driving the water pump pull more while driving under load and will suck it closed most lower hoses have springs in them so they dont do this good luck

Re check hoses is a good start, also check for a thermostat, running in garage is one thing on the road another. If missing or stuck open will not give coolant time to cool between cycles. Check fan clutch for operation at operating tempature should have a severe noise increase ans air volume increase 15-20x when reved over 1500 rpm. Had a F*&^ van drive me nuts one time and would cool ok in shop but overheat on road... bad radaitor, partially plugged at bottom, take a ir theromoter & look for hot/cool spots in core, just because its new dosen't mean its good. Freash rebuild?? check for exaust gas in radiator, poss leaking head gasket will do it too. Blue water chemical turns yellow take it apart it's internal....
Good luck
Brad

Thanks I will pass that along. Good stuff.

Neil

Check that the timing isn't retarded too far or most of the fuel will be burning in the exhaust where it heats up the head quite a bit.