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Enterior windows frost up

I own a 1999 Olds Alero. The enterior windows frost up on the highway, while idling, the windows defrost. I need to continually add anti-freeze and my mechanic can not figure out the reason for the anti-freeze lose. I recently replaced the thermastat. That did not help. I beleive the anti-freeze lose has something to do with the frosting windows. Can anybody help?

A heater core leak will allow coolant to be evaporated and blown into the car as very high humidity air, fogging up the windows. Have your cooling system pressure tested and watch for a drip out the A/C drain, which is part of the heating system, or check for wetness in the passenger footwell as heater leaks will sometimes drip there, right above the passengers toes…(the heater box)

In addition to the above post, check that you heater air switch is on fresh air, and not the recirculation mode. The recirc mode will keep all the moisture and stale air in the car. It’s used for quick warmup and quick cooldown only.

When the defroster is on, it automatically switches to the fresh air mode. I will pay attention for wetness in the passenger footwell. Thanks

Hmmm…“Enterior windows”…do you mean exterior or interior, or is this a new compound word meaning both exterior and interior?


I will assume that you meant “interior”.

The combination of symptoms (frost on inside of windows, plus loss of coolant) certainly points toward a leaking heater core. Just be aware that replacement of the heater core on most cars is the classic “cheap part, very expensive labor” situation. On most vehicles, the heater core is very difficult to access and sometimes requires removing the dashboard and also recharging the A/C system.

However, this is not a repair job that is safe to defer, owing to the hazardous nature of having to breathe aerosolized coolant fumes. Unknowingly, I inhaled this stuff inside my car for several weeks, back in 1991, and I wound up with some nasty lung damage as a result. Have the car assessed for a leaking heater core, and if necessary, have the repair done a.s.a.p.

I had the heater core checked for leaks. My mechanic pressure tested it over night and said there is no leaking. He doesn’t know why we have to add anti-freeze all the time. He cleaned debris out of the vents and repaired a crack in the plastic covering surrounding the front bumper, thinking maybe too much air was getting in. The windows still frost up. I still think the anti-freeze lose is the key. My mechanic is bsffled. Help.

Wouldn’t an “interior” window be a window between the front seat and the back seat? I don’t have such a fancy car. All of my windows are in between the inside and the outside.

The windshield defrosts okay, but the interior side of the rest of the windows frost up. I can scrape them on th inside with an ice scraper. If I let the car idle for a while, all the windows will defrost. After about 15 minutes of highway driving, the windows frost up again. This car is not a bit fancy, especially since I live in Northern WI. So, I can’t see half a year. The windows are fine in the summer.

How is the carpet? Check driver and passenger side both front and back. Is it wet or damp?

I would consider cracking the windows to allow more outside air in. Yea, it will be cold, but if you have wet carpet you need to get it dry. If you find you have damp carpet, you need to decide if it was snow that was brought in or from some sort of leak somewhere. If snow or leak you still need to dry it out. A really long drive or some sort of small electric heater, carefully placed in your car where it will not cause damage with the windows partly open can help dry it out. If you have an attached garage, park it there, open the car door and have a fan blow air through it.

VDC Driver, You Forgot Something!

"In a previos post you said " Folks, you do not “loose” your brakes when the fluid boils. When the drain plug comes out of your oil pan after going to Jiffy Lube, you do not “loose” your oil. The correct term in those instances is LOSE. "

Take a look, again. This new question made me aware that you you left out “loss” !

Your lesson should have included loose, lose, and loss. I warned you that you could loose your mind trying to keep up with the lose of language skills and and all this improper grammar increasingly on the loss.

I loosed track of your original post. Maybe you should include “lost”, too.

If you have a 3.1 or 3.4 V6 an intake manifold gasket leak could cause coolant loss. The Alero is listed as part of the GM Dexcool settlement. Unfortunately it may be too late to file a claim. Have the mechanic check for coolant in the oil or take it to a dealer to check.

If there was a heater core leak the smell of antifreeze should be present in the car.

Everybody Knows That Enterior Windows Are Side Windows.

Think about it.
Anterior windows are windshields.
Posterior windows are back windows.
So, enterior windows are side windows (That’s all that’s left.)

This isn’t rocket science!

Actually in your example “lateral” would be correct.
lat?er?al [ l?tt?r?l ]



  1. at side: relating to, located at, or affecting the side

No results found for “enterior”

We didn’t find a match on “enterior,” but we found the following alternate spellings for you. Click one to continue your search.


All courtesy of Encarta Dictionary

No, Actually The Term “Lateral” Enterior Windows Would Constitute A Redundancy.

Does the heater core always leak inside the car? or can it leak outside aswell?
is replacing the heater core in the alero a do it yourself job for an experienced home mechanic?