I had the same problem. The answer to your problem is simple. You have an air pocket in your cooling system. Simple fix - take the radiator cap off of the radiator, turn the vehicle on and let it run for 1hr to remove the air from the system. Also, make sure your overflow container is atleast at the minimum level. Answer If your certain you have all of the air out of the cooling system the blend door inside the heater box may be stuck open.
The heater might blow cold air in a 2000 Silverado because the thermostat is sticking and not changing from cold to heat. The thermostat is usually located in a hose that leads from the radiator to the motor.
Try flushing heater core Try flushing heater core
Have you flushed the heater core?
Before CHanging the Heater Core, have you tried flushing it? I have a 99' Jimmy and have to do this every year to get my heater to work.
Heater Airbound? Heater control cable not working? Heater core plugged?
possibly thermostat stuck in the open position?
What temp. thermostat did you put in? Try a higher temp. one. or check to see if heater core is clogged
could be a bad thermostat try replacing it answer try flushing out your heater core also
Your heater relay switch may be bad
probably the heater core is clogged
try the bend door
If the engine is overheating, the thermostat is stuck closed. If the heater is not putting out enough hot air the thermostat is stuck open. Change the thermostat as a normal part of maintenance when changing coolant.
start by changing the thermostat
Poor coolant circulation from a plugged up heater core. Try flushing the heater core and replacing the thermostat.
Could be low on coolant or the thermostat is stuck open.Could also try flushing the heater core.
Flushing sometimes frees up mineral deposits that then clog up your heater core. My mechanic told me to never flush a Toyota as the heater core was low in the engine. That is, only drain and fill when doing a coolant change to prevent dislodging the deposits.
Heater core (radiator) needs to be cleaned or changed
Try the thermostat, second see if the heater core is plugged up if that's not the problem see if the engine is even running hot enough
more than likely the coolant level is low otherwise check that the thermostat is functioning properly. if neither of those seem to be the prolem than you possibly have a blocked or bad heater core
Normally this is caused by a thermostat that is stuck in the open position. Replace the thermostat. If you are only referring to the heater reaching the correct temperature it can be a bad thermostat or the heater core can be clogged . You can try back-flushing it to remove any clog but may end up having to replace the core which is always a time consuming job.
The heater core is bad that's why you do not have any heat
had a similar problem with dodge caravan, tried all sorts of thing like changing heater core, thermostat ,heater control valve and pulling radiator and flushing entire system turns out the the fins on the water pump were worn down and wouldn't pump the coolant didn't think it could have been pump as it was replaced not even a year ago hope this helps good luck
A heater thermostat controls the temperature of water in a heating system. A heater thermostat can be purchased from companies such as Hygiene Supplies Direct and Alibaba.