How do I repair a clogged heater core? - Cars & Trucks

Some things it could be but not specific to your vehicle.
Do you smell antifreeze? Engine temps running hot? Has it run hot?
No antifreeze in radiator, when cold take radiator cap off and look to see if it is full. add as needed in radiator and overflow container.
Heater control valve not working properly or inop.
Clogged heater core. Leaking heater core-heater core bypassed.
Heater box door not operating properly or inop.
Vacuum leaks or broken lines/cables.
Intake manifold leaks
Clogged radiator
Could be many things, checks/tests need to be performed to determine the cause either by you or a certified repair shop.

Heater needs Heater Core, Heater control valve, air diverter inside the car and hot water in the heater core. If you just change the thermostat you must have had a reason. If the car was running hot it could be a radiator clog. If the core is clogged no heat. If the heater core was drained when you changed the Tstat there may be air in it - if so no heat. If the control valve (on the heater hose) does not shift- no heat. If the diverter door in under the dash does not direct the fan air through the heater core- no heat.

Charles,when they get clogged,you must replace,need help doing that,if so then we need the year,make ,model and engine size.

Try at www.rockauto.com

Good luck

Mai

A clog can cause low heater perforance in the winter. I had a 1990 Cadillac Deville that had cold air blowing in the middle of winter, and had the system flushed and that solved the problem.

One can feel the two heater tubes at the firewall leading to the heater core to verify whether or not the antifreeze/coolant is getting hot at the heater core.

Good luck on this repair.

flush your system the heater core may be clogged hope this helps

Things to check out Freshness of coolant(when was the kast time it was replaced)
Thermostat,Blend doors aka heater valve (I believe you model works off a cable) test it to make sure it is operating. Lastly heater core, it may be clogged or if coolant is leaking inside the vehicle its shot.
Remember if you determine that heater core is clogged you maybe able to remove the clog with a fluid exchanger machine. There are shops that do this type of service. But the best repair is replacement.

It could be the thermostat, or a clogged heater core. The heater core runs off of the cooling system, radiator etc. If the heater core is clogged the heated water in the system cannot transfer through the heater core so you will have no heat. If you're still under warranty, go back to the dealership. Worst case, take it to a service center like Goodyear, explain your problem to them and ask for a quote to repair it. Now you get free diagnosis and now where to start the repair if you want to on your own. Otherwise, if you think the price is fair, have them repair it. I hope this helps and good luck!

you can try to flush it out by removing both heater hose going into the core and coming from the core. Hook a garden hose to the hose going in and then try flushing the hose going out. Normally once a heater core is clogged there is only the option of replacing it.

it sounds to me your heater core is plugged. you can try to back flush it,being this vehicle is twenty yaers old,i would say to replace it