Flushing of Heater Core

1999 Ford Taurus with no heat. I’ve replaced the plugged heater core twice during the last few winters. Is there a way to flush the heater core to remove any plugs deep inside? I’m thinking along the lines of a drain cleaner concept.

Any ideas?

If you keep replacing the heater care and you’re still having problems, perhaps the problem lies elsewhere. Perhaps there is a valve in the heater hose that opens and allows the hot coolant to flow that’s malfunctioning. Perhaps your blend door in the ductwork isn’t functioning. Perhaps your thermostat is stuck open and the engine isn’t reaching operating temperature.

I suggest you get a manual and start looking the system over as a whole. The heater core cannot possibly be plugging up annually.

Wow! I’d hate to see the bill to replace the heater core in a Taurus TWICE. It’s an expensive job. A heater core should last longer than a few years. There is, I think, another problem.

Having said that, when the cooling system is flushed, the heater core should be flushed as well, since it’s all part of the same system.

It’s definitely the heater core that gets plugged. I’ve purchased and installed two of them and both of the old ones were plugged. I’m just looking for a way to unplug instead of replacing.


Boiling works, however you have some other root cause. Have you tried flushing the cooling system as McP suggests? What type of antifreeze have you been using? Dexcool???

I have flushed a heater core with a garden hose. Hook up the hose so you are flushing the core in the opposite direction from the normal coolant flow

I have flushed the system more than is necessary because of replacing the heater core. I use only Prestone engine flush and then Presone antifreeze. I do all the things I think I should. Maybe I’m going cheap-o on the heater core itself!

Thanks for the advice - I’ll try flushing it a few different ways and report back.

I would avoid the engine flush, I have had nothing but trouble from them so I don’t use them anymore.

Do you know what is plugging the core, is it a build up of minerals or something like rubber or just a gel like substance? If minerals, I’d recommend using a 2:1 ratio of antifreeze and distilled water. If you’ve flushed out the system with a garden hose, drain it and fill the system with pure distilled water and drain again. It will cost you less then $2 to do that.

Back flushing is the way to go. Cleaning fluids can only work if there is a flow already. If it’s plugged, then the cleaning fluid can’t reach the obstruction.

Any chance you, or someone else, used Bars Leak or some other cooling system remedy in the past?

FIND OUT WHY THE HEATER CORE IS GETTING BLOCKED,underline the word WHY,then sit and ponder on how much BARS STOP LEAK you or a previous owner dumped in the RAD.

theres your answer.