Need Automotive help: Pontiac Montana front window defrost problem.
We own a 2002 Pontiac Montana mini van. Last winter, in upstate NY, when the weather was below freezing the defrost would not clear the entire front window. I took the van to the mechanic and they cleaned the cabin air filter. That did not work so I took it too a different mechanic who said the carpeting was wet and the fan was sucking up the moisture and told us to dry out the carpet. It still did not fix the problem. What exactly happens is the window defrost will sound like it is blowing, it is blowing some but the window still fogs and below freezing the window actually freezes to where you can not see out. I really would like to get this fixed before this winter.
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4 Answers
You may have squirrels or other rodents making nests under the hood. Ever have an acorn fragment fly out of any of the ducting when you turn on the blower after the summer ends? That’s a dead giveaway.
If there’s little or no air flow out of the vent, then your duct is blocked. Because if you don’t have excess moisture in the vehicle, and you do have air flow, then your glass will clear. So I’m about 90% confident that you have a blockage in the duct.
For me, mothballs tied up in nylon stockings under the hood of the car has helped to keep the ducts clear, and I can put up with the faint odor of mothballs in the cabin.
Are you using the recirculate mode on the heater? If so stop. The recirculate mode traps the moisture in the car, fogged up windows and frost on inside of windshield can be caused by recirculated air.
Final idea is see an air conditioner specialist, they may have to take the ducts out from under the dash and clear out debris ( pencils, pens, coins… etc. )
I assume you are getting air flow but you still fog up. Here are a couple of choices: one easy, one difficult.
Easy: Your car has had all season to build up moisture in the duct and water has pooled in it. Run the heater with outside air for a while and see if you can dry it out. Park in the sun.
Here’s the difficult (bad) one: You might have a pinhole leak in your heater core and are dripping a tiny amount of antifreeze all the time. Do you see antifreeze on the carpet? Are there any odors? Changing a heater core is a pain. Before you do that, throw in a can of Bars leak stop. You might get lucky.
Let us know how you make out.
Thank you worriedguy, as disconcerting as this may sound, at least it may be an answer.
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