C-15 losing coolant from overflow

Head gasket

 

On that line of thinking,then tell us how water that is not moving from the engine to the radiator is being cooled?We just went through this exact problem on my brothers 1LW cat.We took water pump off and u could spin inpellar with ur finger.So yes,it can have everything to do with loosing water.

 

It had a coldwater weep.But an Hr with a trusted mech should yeild the cause of ur problem.Good Luck

 

Pushing water out the overflow is what I was talking about.

 

could be air in system most trucks the tank is just an expansion tank like the one on the fender in your car if there is air in the system what you put in tank will just push out the overflow. see if there is a petcock on your upper tube to the radiator and if so bleed it out there

 

Time to replace the head gasket.

 

I understand.Just thinking of the few ways of loosing water.Water getting to hot,cracked head with water going out exhaust,blown head gasket puting pressure in system,bad cap,bad water pump,air getting in system from compressor or from air valve in bunk that goes from cold to hot water.I know most of us try to help with differeent problems and it helps us be better troubleshooters.

 

a pressure test may help finding where the problem is