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Inside windshield frozen over HELP

I will try to make this as short and informative as possible to help you help me. My Sable is a 2001,spending 3/4 of it’s life in Texas. 115k miles. A relative sold it to me cheap and brought it to where I live in Central New York (had 70k miles at the time). The heat was not used once while in Texas. After the first winter here, my heat stopped working. I have tried a few things to get it working, including flushing the heater core every year- which barely helps for about 2 weeks. Now last year, the driver facing blowers stopped working, so only the front and back defrosters push out only cold air.
On top of this, I know where moisture enters. The windshield was poorly replaced and someone gerry rigged a sealant on the outside of the windshield. Small bits of moisture seep in, thus frosting my windshield over. I have brought it to several mechanics who’s only diagnostic is that the heater core needs to be flushed- costing me $100 for something I can do myself. I can’t put alot of money into this car and was recently denied a car loan, since I don’t rely on credit. I’m just looking for tips on potential heat fixes, I also plan on resealing the windshield the proper way in a few weeks. Oh and I used to smell coolant when I ran the barely working heat, but that stopped last year as well (no more smell). I have considered putting silica gel packets throughout my car to help eliminate moisture. I’m almost positive that my thermostat has been replaced too. Please help, I am tired of driving in these dangerous conditions.

I believe that the most likely cause is a leaking heater core. Just be prepared for a very large repair bill, as this model requires the removal of the dashboard in order to access the heater core. I know that because my Taurus–which was mechanically identical to your Sable–had the same problem. The heater core itself is relatively cheap, but the labor costs involved in changing it will be…very high.

In addition to the obvious safety hazard of trying to see through frosted-over windows, you should be aware of the health hazards involved with a leaking heater core. The aerosolized coolant that you and your passengers are breathing can lead to VERY serious respiratory problems–which I found out the hard way with my Taurus.


Agree! The heater core is a $60 or so item, but labor will be 6-8 hours! We had a Ford Granada with a flimsy heater core and my garage got it changed in 5.5 hours, total cost $550.

So, budget at least $600 and seek out a private garage with a good reputation.

Good Luck!

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If my memory serves me correctly, I believe that I paid ~$600 to have my Taurus’s heater core replaced, with ~90% of that amount being for the labor.

Thank you both for replying. I honestly figured as much. I knew it was leaking. I forgot to mention, I used a sealant February of this year due to frequent overheating as well. It was brown liquid with little black beads in it, and it has done its job since then. Does this confirm this problem?

That is a lot for such a cheap part lol. Oh well, I’ll get it done in a month or two. Did it work really well after?

As for the windshield . . .

The only proper repair would be to remove the windshield, clean off all the old glue, prep the sheet metal and the glass, and reinstall, with new glue

However, from what I hear it’s sometimes tricky to remove a glued-in windshield, without damaging it in the process

So the most realistic solution might be to simply have a new windshield installed

A note of caution . . . considering the car’s location, the fact that the windshield was incorrectly installed and sealed, and the age, I feel there is a possibility that the sheet metal below the windshield might be rusty, or even rusted out.

I agree . . . it sounds like the heater core is beyond help at this point. Don’t waste money or time on flushing

Your air flow seems to be in default mode. That sometimes happens when a vacuum hose becomes disconnected or rots away. It’s been awhile since I’ve worked on a Taurus/Sable ac system, so my thinking might be wrong

Considering the age of the car, its value, and the location . . . I’m thinking it might be very rusty by now, and perhaps close to failing a state inspection . . . I feel it may not be worth it to invest too much money

Sorry this all sounds negative, but I call it as I see it, based on the information at hand

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I actually never had any problems with the heater while it was leaking, and the heater continued to work just fine after the heater core was replaced.
Unfortunately, it took my lungs a long time to recover from inhaling that aerosolized coolant for a few weeks.

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No it’s not negative, my car just needs a lot of TLC… or a scrap yard :slight_smile:. Do you know of any DIY solutions I can make up at home to help clear away the frost on the inside of windshield until I have money to fix it?

Actually I found online I can use a solution of 1 part water, 3 parts vinegar in a spray bottle. Using a cloth to wipe it off. Does anyone think that will work for now?

I think that you would have a much better chance of removing the frost with alcohol.

These are great at plugging up small leaks and passages, just like those in your heater core. If flushing the core results in a small amount of heat for brief periods, I think that helps support the idea that the stop leak also stopped up your core.

I also plan on resealing the windshield the proper way in a few weeks.

Will you describe how you intend to do this? Just curious because ideally, you’d need to remove the windshield, clean off the existing sealant and then reapply the correct sealant before reinstalling it. Not many DIY people can/will attempt this level of repair. Windshields are unwieldy and prone to breakage if not properly supported. The sealants are critical as well since the windshield is an integral part of the structure of most cars nowadays…something best left to a pro…

What you’re describing makes me think you’ve got combustion gases entering the coolant, possibly due to blown head gaskets

Does your car happen to have the 3.0 liter Vulcan engine . . . the base OHV engine, that is?

If so, that is a fairly common scenario

Here’s how to replace the heater core in your Sable without removing the dash.


How did u flush heater core? I just did it and it is not easy. The heater hose assy has a bypass that routes coolant around heater core if it is plugged. I don’t think u took off inlet and outlet hoses at firewall cuz u would have mentioned that sorry task.

If you smell coolant with the heat in the on position inside the passenger compartment there’s something definitely leaking, but it isn’t necessarily the heater core. Could just be a hose or connection that’s leaking. I think the first thing I’d do w/this problem is temporarily disconnect the heater core outflow in the engine compartment at the firewall, and observe how much flow I was getting through the heater core. You’ll have to refill the cooling system for what coolant you lose doing the test of course. Once you measure that heater core flow, then you have something to go on for what to do next.

If the windshield leaks you may be able to get it to stop by applying some more sealant along the seam as a temporary fix. I was able to stop my truck’s windshield from leaking that way. I admit the fix doesn’t look pretty, but no leaks.

The more common way water leaks into a car is through the doors and through the drain vent system. Some of the rain water that hits the door windows always runs down and inside the door. That’s by design. It is then supposed to drain back out to the street via drain vents in the bottom of the door. Make sure those vents are clear, otherwise that water can find its way onto the car’s floors instead. Likewise there’s a drain path provided for water that goes into the air vents under the windshield. Make sure that path drains freely too. Water can leak into the trunk if there’s sealing problems with the exterior lights in back too. Good idea to pull up the carpets as best you can and look in the spare tire area of the trunk, see if any water is accumulating.