Moisture build-up/Heater HELP PLEASE!!!

[ryans69chevy]

Does anyone know what could be causing the windows on the inside to fog up and then freeze after the heater is started?

It's very dangerous to drive when this happens...steering with one hand while scraping the windows with the other. I'm not really sure what is causing this...I thought it was my weatherstripping on the doors so I replaced it with a temporary weatherstrip. This fixed one of the problems which was the windows were freezing on the inside before I was even in the pickup. But now it's freezing all the windows when I turn on the heater. Has anyone ever had this happen or know how to fix it?

I'm thinking maybe it could have something to do with the heater core box under the hood. Since I pop my hood slightly to get an extension chord in there to plug my lower radiator heater hose in. I don't know if this is normal to have a heater core box that is in two pieces and that don't connect all the way like a 1/4" gap maybe snow gets in there and melts which causes moisture to flow through the defroster hoses? I'm going to put a piece of duct tape over the gap today. Or could it have something to do with my antifreeze mixture? I drove this truck all last winter and don't remember the inside of the windows freezing up....

Thanks for any advice

[dan76]

For a temporary fix, try duct taping the gap in your heater core box to ensure no moisture gets in. Probably what's happening is moisture is in the vents and when warm air hits it's carried onto the glass where it condenses and freezes.

[raycow]

Probably the one answer you don't want to hear, but I would suspect a core leak. The water vaporizes in the warm air stream and then condenses when it hits the cold glass.

Ray

[54blackhornet]

If the heater core is leaking you should see fluid it coming out of the lower hose outlet on the heater core housing under the hood. Could be leaking and getting blown into the cab when fan is on. My 71 did that untill i saw the leak !

[dan76]

Originally Posted by raycow

Probably the one answer you don't want to hear, but I would suspect a core leak. The water vaporizes in the warm air stream and then condenses when it hits the cold glass.

Ray

I originally thought this also, but the poster didn't indicate he was getting a film (of antifreeze) on the glass as moisture was freezing on the glass. Since he is experiencing freezing temps, I assumed (yes I know what happens when one does) he was running a coolant mixture rather than straight water.

Though if he is experiencing a heater core leak, it's a quick fix with a new core running about 25.00 from AZ.

[ryans69chevy]

So if my heater core is leaking, I would be able to see it dripping out of the box while it's running, or would I most likely have to take the box off and look at the core itself and find a leak there?

Thanks for the help guys

[raycow]

Originally Posted by ryans69chevy

So if my heater core is leaking, I would be able to see it dripping out of the box while it's running

If the core is leaking, I would think you are more likely to see it dripping out of the box when the fan isn't running. This will keep the water from being picked up in the air stream.

If you don't see it dripping and the problem still persists, then I would say you will have to pull off the box.

Ray

[Jacfourteen]

also if the heater core is leaking you will notice that your coolant level in the rad will drop.

[cdowns]

your rad level wood b droping with each use of truck//you'd also have the distinct smell in the cab of antifreeze// i'd doubt very much leaking antifreeze will freeze to ice on windshield

i'd think it is more likely that you have a rainwater leak that is puddling up in the heaterbox or in the kickpanels or cowl area of the truck

[grs]

Mt truck does the same thing, but it has Vintage Air in it. This will happen with Vintage Air.

[Jacfourteen]

Originally Posted by grs

Mt truck does the same thing, but it has Vintage Air in it. This will happen with Vintage Air.

This is due to the lack of outside air which leads to moisture build-up in the cab. To counteract this you can open the passenger side kick panel vent, but it's kind of counterproductive to blow in cold air when your trying to heat it up.

[ryans69chevy]

Okay, everything sounds good! Thanks for all the help so far. Tomarrow, I will search closely for the problem and I'll ask some more questions if need be.

Thanks!