Heat is a nice thing to have have here in da "YouPee', the problem is that I have none. Background... '03 SuperCab. 170.xxx. Arizona truck so not a rust bucket. Back in late Oct last I went to park my 22' trailer at a friends place for the winter. Truck was idling as I hooked it up and showed normal temp. Drove it 1/2 Mi and had to pull over and shut it off as the temp was pegging on hot. Fired it up a coupla min later and the temp started dropping down to normal and has been there since. Fast forward to this year in Feb. suddenly no heat. Added more coolant than I expected to and had heat again. Yesterday when our temps dropped suddenly no heat. Engine temp was normal and I've topped the bottle up 2x today without luck. Thermostat?

 

You might want to change your thermostat when you repair your coolant or head gasket issue.

 

i had a minor head gasket / etc.. leak.. Would use a small amount of antifreeze over a month until NO HEAT... Then you had to top the radiator off again... I ended up putting a bottle of BARS COOPER HEAD GASKET SEALER into the motor ( 2001 F150 ) and that seemed to seal everything up. Really didnt want to get into a HEAD PULLING program with an older truck.... Pull the top radiator hose and pour the 16 oz bottle into the hose ... dont add to the overflow tank.

 

It turns out that the blend door activator had failed. Had it fixed and now I have heat again

 

????? so where did the antifreeze go ??

 

exactly. hvac may work for now but cooling system still has issues.