the heater control valve it stuck closed for some reason. Check for a broken vacume line between the heater control to the valve. With the engine running check for a good vacume at the valve with a vacume gauge it should be close to the same reading as the engine vacume. If all is good then the valve is bad GRUNGE BUILD UP ON EVEAPORATOR (CAUSED BY LEAK) AND BLOCKS INCOMING AIR TO HEATER CORE AS IT IS IN FRONT OF IT. YOU WILL HAVE TO PULL THE EVAPORATER TO CHECK. I KNOW OF 2 INSTANCES OF THIS ALREADY INCLUDING ME ; ) GOOD LUCK. There is a seal that sits behind the heater core and fire wall where the hoses connect to the heater core. You can get an air leak there and cool air will be produced by your heating system. To check: with blower running squeeze your hand down by the heater hoses in the engine compartment. If you feel air coming from the blower motor then you will need to seal the leak. you also have a seal that is on the inner cover to the heater box that covers the heater core. That can cause some air leaks also.
Heater core (radiator) needs to be cleaned or changed
Replace the coolant, thermostat, turn off the A/c, in emergencies drive with the heater on, increase the air flow through the radiator, have your radiator checked for blockage.
Your thermostat might be stuck open. Does the radiator cap get hot after running the engine for 10-15 minutes? If not, replace the thermostat.
Check the thermostat or the radiator. The thermostat could be sticking or the radiator could be plugged.
could be several things. have you tried replacing the heater core. if not that, call a mechanic. you probably won't be able to fix it unless you know what you are doing.
Maybe a stuck thermostat, or a broken radiator/heater hose. Sometimes the radiator itself blows a seam. Water pump seal, blown head gasket, etc.
The temperature of the coolant entering the heater core is controlled by the engine thermostat. The engine coolant thermostat is generally located at the engine end of the upper radiator hose.
Change your thermostat. Mine had the same problem and it was stuck open.
It will take a little longer for the cooling system thermostat to open up if the heater fan is on. The heater fan and heater core act like a small radiator and disperses heat energy when in operation.
It could be the thermostat. Open up the radiator cap when it is hot and see if the water is flowing in the radiator. If it is not then it may be a thermostat.
test flow in and out of heater core it may be plugged or need replacing, if it is not plugged up check temp controls, may be stuck in vent or a/c setting.
most likely you dont have enough coolant to reach heater core. make sure your full
You may have an air lock in the heater pipes some vehicles are fitted with bleed screws for this purpose.
Could be: Low coolant in the radiator - or - thermostat stuck open - or - heater core plugged.
Your heater core is plugged and you need a thermostat.
the heater control has a thermostat for the heater only. that thermostat needs replacing
the heater hoses usually lead away from the thermostat and go into the fire wall. On the other side of the firewall is the heater core. the top hose on the radiator goes into the thermostat most of the time
you might need a heater core
follow the upper radiator hose, that should lead you to it.
No there is no freon in the heater core just antifreeze. The heater core is nothing more than a tiny radiator.
one large hose from bottom of radiator to side of water pump. other large hose from thermostat housing to top of radiator. one heater hose from water pump to heater core, I think this one has a Y in it if there is a rear heater other heater hose from heater core to somewhere on top the engine. If there is a rear heater, its return hose goes to a fitting on the radiator.
Leaking radiator radiator hose head gasket water pump Heater core thermostat housing
could be a bad thermostat try replacing it answer try flushing out your heater core also
check the thermostat dude may need replacing
Have you checked your thermostat?