Coolant expansion tank repair

I have a 2001 Ford Taurus with a leaking coolant expansion tank. The tank is cracked and there are 2 pinhole sized holes in the corner. It’s a plastic tank and it is under pressure. Last night I discovered the leak and used epoxy to try and fix it. I drove today and the epoxy seems to be holding up fine… so far.

My questions: How long should the epoxy patch hold? Is this a long term fix or do I need to replace the tank.? Has anyone used this method for this type of repair?



Replace it.
Plastic and time are not friends, you will have nothing but future troubles trying to fix it.

I would replace the plastic tank. Your repair will last until it fails. Who knows how long that will be.

You could try finding a tank in a junk yard if you don’t want to buy a new one.

I’m going to suggest epoxying a patch of fiberglass over the existing patch, with plenty of overlap onto the good areas of the tank sides. That’ll keep you safe until you can locate a boneyard replacement.

Hot coolant under pressure? (Are you sure it’s under pressure? If you asked me, I’d tell you that expansion tanks are at atmospheric pressure, but I’ve never really thought about it.) I doubt the patch will last long.

But I’ve been wrong before. A patch on the inside of the expansion tank might work better. But the last time I had a crack in an expansion tank, I just picked up a replacement at a junkyard for – as I recall – $10.

This vehicle has no cap on the radiator itself, the only opening/cap is on this coolant recovery tank. This is under pressure.

If I were the vehicle owner I would get a different tank. A new one is around $60 for this car. The patch on the current tank may fail at the most inconvenient moment.

In that case it is probably properly called a coolant degas bottle or reservoir.