My windows fog up in winter months

[Joe Pawlowski]

My side windows fog up excessively in my daily driver in cold winter months.My defroster blows,heater works,cant find any drafts,just tired of constantly wipeing windows with towel.Has anybody used any of the anti-fog products and had any luck?Thanks-Joe

[Doug's 73 Cutlass]

Joe,

I have the same problem on my 73 Cutlass. I found out from a couple of people on this forum that the problem is due to a leaking heater core. Check the carpet under the passenger side dash for dampness. That's a sure sign your heater core is leaking and needs replacement.

Doug

[1977 Cutly]

I guess I'd better check out my heater core. I used rain x anti fog on my interior glass, and eliminated the fogging.

[Joe Pawlowski]

Well,dont see any signs of a leaky heater core as of yet and no sweet smell in the air,at least not from anti-freeze.I tried rain-x anti fog and it worked like a charm.Thanks/Joe

[custom cutlass]

Moister has to be entering your car from somewhere, door glass weatherstrip, quarter windows leaking, has the cardboard vapor barrier been removed from underneath the door panels, these are just some reasons why your vehicle may be getting moister in it.. You will smell a obvious antifreeze leak in your car as soon as the thermostat opens if you have a heater core issue.