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1995 Ford Escort that has had the heater core fail 3 times in as many years

My 1995 Ford Escort Station Wagon LX, 1.9 liter engine, has had the heater core fail 3 times in as many years. It always seems to fail in the spring, but can’t positively verify that it has only happened when I began using the air conditioning. It is something I started thinking about this morning. I had the motor mounts checked the last time it failed and there was no problem. Incidentally to this problem, I have also had the head replaced; I mention this because the first mechanic that replaced the heater core thought it could be causing the problem. Is there anyone who can provide some insight? Thanks.

Exactly where is the core failing? If it’s the joint between the inlet or outlet pipe and the core end tank, there’s vinration and/or lateral stresses occurring on the pipe. It’s possible that someone cut the hose a bit too short during one of the replacements.

If the core itself keeps rotting out, than I’d suggest that acidic water is being used rather than distilled water in the coolant mix. I’ve seen acidic water eat through plumbing pipes, which are a lot thicker than your heater core tubes.

The two that I’ve seen after replacement had the joint failed. Or as I would explain it, there is a weld between the main body and the tubes or pipes sticking out, and one of the welds was broken on each of them. Hopefully that makes sense, as I am not a mechanic and have never seen one installed, just the failed one after removal. Are there any other possibilities for vibration that might cause the problem? I would really like not to have to replace this but once more. I am really tired of all the antifreeze and water that leaks onto my front floorboard, as well as the constant worry that the car is going to overheat and mess up something else. Thanks for your help and any ideas you might have.

Hoses that are too short will yank as the engine flexes under acceleration.
( speaking of engine flex )
Check those motor mounts to see that the engine flex isn’t perhaps the true cause.

With the hood open, look to see what the engine does as someone else pushes the accelerator both in park and in gear while holding the brake.

The last time the heater core (and head) were replaced, the mechanic checked the motor mounts and said they were okay. Since I ran over a dead deer a few weeks ago and the heater core has since failed, I did the above test, or a facsimile since I have a manual transmission, and all seemed to okay still. I would guess at this point that the motor mounts are not the problem, that the problem lies elsewhere. Thanks for your help.

Can you post a photo of the installation?

More often than not the type of failure you describe is because a hose is too short, with an insufficient “stress relief loop”. Often it’s because when the original core was removed, it was done by cutting the hoses at the pipes.

Not sure what you want. The installation of the heater core in my car involves taking out the dash, and until a new one is installed I have no plans to take my dash apart. Within those parameters, is there something I can take a picture of that will help?

I was thinking of the heater hoses going to the core, if you can possibly get a shot of them.

The other thing that ruins new heater cores usually doesn’t wait a year to show up.
When installing the heaeter hoses on to the new core it is common to both push and twist multiple times to get the hose squoosed on to the tube nipple.
This twisting and pushing and wiggling wobbles the tube at the weld weakening it like any piece of wire you bend mutiple times.

Is this where your leak is ?