My heater will quit blowing out heat but when I put antifreeze in it starts working. I have bought 2 gallons of antifreeze in the past month and it keeps evaporating but I don't see any puddles anywhere. My heater will start working after I add the antifreeze.
There are no visual leaks or puddles?I would start by getting a coolant pressure tester and pumping up the cooling system and look for leaks. Check the cap also if you find nothing there you will have to do a chemical test to check for a blown head gasket.