My car heater is blowing cold air

If the coolant level is low in the engine it can cause heat fluctuations from the heater, as well as an incorrect reading on the gauge. Make sure the coolant level is correct in the engine.

Yup, flush the coolant ayatemavoid using Barsaleak type leak treatments for leaks. They are notorious for clogging up.heater. cores.
a fresh air actuator door can also get stuck open allowing cold fresh air which in wintertime feels like no hot air at all. I think this door is actuated by vacuum hose.

Hi, if the temperature gauge read zero then the thermostat is gone.
If it's just no heat and the gauge on the dash is reading normal coolant temperature then it may be the Coolant Temperature Sensor. If the heater core was gone there should be a leak inside the car somewhere. Hope this helps

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These details will help.
Thanks.

Could be a thermostat problem or your heater core!

low coolant sensor is probably just dirty. cold air could also indicate n air bubble in the line. could also be thermostat. try that first.

check coolant level in radiator and coolant bottle sounds like it may be low on coolant

Definitely check your fluid level in your radiator. Top it off all the way. I've seen that happen multiple times on cars that were low on anti-freeze. If that doesn't work try replacing your thermostat. It's cheap and the easiest place to start if topping off the fluid doesn't get you fixed up.

check coolant level ,must be low ,chck for coolant loss

check your coolant level on the radiator