Do I Have a Heater Core Leak or Rain Water

heater core leakPlease help me. I do not want to make an expensive mistake. I am not working – I take care of my elderly mother and I am a single parent.

My car is in the shop, this is a new garage for me, but my neighbors have used them for years, say this garage always fixes their cars right.

The garage left me message on answering machine – My 1995 Buick Skylark 6-Cylinder needs a heater core.

My car has several problems – some may have misled the mechanic to a false conclusion, maybe not.

There are five problems:

1. For over a year, water has been getting into my floorboard, mostly on drivers side, but some on front seat passenger. This always happens after a big rain, or if I wash the car. The water shows up the next day. There is a bit of debris stuck in the valance below the windshield, and I suspect there is more inside the drain below. If I keep the car out of the rain, there is no water in the floorboard. Period.

2. The heat in my car only comes out in the higher vents, will not come out through the floor vents. Does not matter which setting you choose.

3. Windshield wipers fluid comes out on tubing attached to the wipers themselves (horrible design). No fluid will come out, if I fill up the reservoir.

4. A year after getting water in the floorboard, I replaced my water pump, because car was leaking water. A few weeks later (after getting new water pump), car started losing water again, and it eventually got to where there was hardly any water at all in the overflow reservoir. Interior dash light would say “low coolant”.

5. Drivers side electric window will not go up or down. It is stuck open about 3 inches. (More water!). My heat works. So why the heater core?

Thank you for ANY help you can provide, or suggestions you can make before I spend a gigantic amount of money that I do not have.



Hey Joyce,

So it sounds like the largest problem and expense is a possible leaking heater core? The core can leak and still produce hot air.

There should be green oily feeling coolant on the passenger floor up under the floor mats, and you would be low on coolant in the radiator if you had a leaking heater core. The mechanic should have done a cooling system pressure test to be absolutely sure that is the problem.

If you are on a tight budget you can by pass the heater core for now to stop the leak, but you won’t have heat until you replace the core.

Here is a video showing you how to by pass the heater yourself.

It sounds like you have a rainwater leak, probably due to all the stuff built up around the base of the windshield not allowing water to drain off properly.

I would clean off the windshield area and visit your local coil operated car wash and have someone spray the glass with high pressure as you sit inside with a flashlight looking under the dash and around the windshield for the leak. I would be highly suspect of the 3-inch hole atop the driver window!

As far as the heat only coming out the defrost vents, you might have a problem with the “blend door” or have a vacuum leak type of problem, which I talk about here.

Please share this with your friends,
Austin Davis

Posted in: A/C and Heating

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