Skip the auto shop - Our mechanics make house calls

Q: Heater only blows cold

asked by on

The blower works high and low but blows no heat, only cold air. It does say check coolant sensor but i dont know if that has to do with the heat blowing cold. If this is sonething simple, i can try to do it myself.

My car has 200000 miles.
My car has an automatic transmission.

Hi There, It sounds like your coolant temp sensor may not be transmitting the proper signal to the computer. The coolant temp sensor helps to control the temperature of the coolant by relaying this to the computer which then causes the cooling fans to come on at specific temperatures which then allow the coolant to cool down. The other possibility may be that your heater core may be clogged or not flowing properly. The [heater core]((https://www.yourmechanic.com/services/heater-is-not-working-inspection) is a small radiator like unit that circulates the hot coolant from the engine through the heater core which then uses this warm coolant to heat the inside of the car with the help of the blower motor that blows the warm air through the vents inside the car. The other possibility is that the thermostat may not be allowing the engine to reach a normal operating temperature and since the engine’s warm coolant is the essential source of the heater core supplying heat to the inside of the vehicle, this can impact the warmth of the heat inside the vehicle. I would suggest having an expert from YourMechanic come to your location to diagnose your heating system.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: transmission

It sounds like you may have a major transmission failure. The transmission is slipping if your RPMs are going as high as 5000 before it shifts. The shuddering is another sign of potential transmission failure. I would recommend having your...

Q: Fuel pump not working, changed it, also new battery and alternator , still no fuel pumping

Hi there. Are you getting battery voltage at the fuel pump? Double check the fuses with a digital volt/ohm meter and measure voltage on both sides of fuse to verify continuity. Your fuel pump circuit should have a relay or...

Q: what is missing rubber piece

This is to help stop wind noise that comes from the gap in the door when it is closed. You may notice a whistle noise from the door at high speeds if that part is not replaced. I think the...

Related articles

How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.