last fall i changed the thermostat in my 1999 Dodge Laramie V10 - everything worked out good. The Truck put in storage over the winter - this spring, on putting it back in service, and using the heater, I notice the windows fogging up (cool day today), and the windows never cleared.. No evidence of any leaks from the heating system. The Air Conditioning works good, and only after the temperature in the Cab cooled ( I was freezing), did the windows de-fog. ANY SUGGESTIONS as to what may be the problem ?

 

Pressure test the cooling system...... Heater core can leak, and it runs right out the drain for the A/C.....

Feel your carpet as well.

 

Thanks

 

yes my heater core was leaking and i couldnt see any coolant on the ground or inside but the heat smelled of coolant. it can weep as well off the heater core but just get burned off (what mine was doing). most likely you need a heater core replacement. is it foggy over the passenger side of the windshield the most?

 

^That's exactly what mine does. Smell of coolant when turning control to hot, windows fogging on passenger side and never clearing, no leak on ground or carpet. Suspect I'll be doing a heater core in the future.

 

yep mine lasted over a year until randomly one day i couple drops were on the lip of the floor vent. replaced it next day.

 

How about " Bars-Leak" - ha ha.

 

I was dumb enough to try the fix in a bottle once, ended up with a completely blocked radiator.