Skip the auto shop - Our mechanics make house calls

Q: My heater only blows cold air

asked by on

I just put in antifreeze and a new thermostat and it's still blowing cold air. What else could be wrong?
My car's transmission is unknown to me.

Check the operation of the heater control valve, which is often located on the engine compartment firewall. If that valve doesn’t move to the commanded position, or move fully, you will have a no heat condition. If the valve is operating properly, then either the blend door(s) is non functional, the heater core in the dash area is plugged, the hoses are restricted, or there is trapped air in the system preventing coolant circulation. If you request a no-heat diagnostic, the responding certified mechanic will determine which of the foregoing potential faults is the cause and give you an estimate to repair.

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: My heat blows out of the passenger vents but blows cold air out of driver vent...what is the issue???

Hey there. The temperature blend door on the left side is not switching from cold to warm. The temperature actuator needs to be replaced and the linkage checked. Have a local expert inspect the cooling system to verify these issues...

Q: Odd wistling noise about above 2 rpms my cats are going can it be that .

Hi There, If your vehicle is a non-turbo, the whistling sound is likely the Secondary air pump coming on when you first start the car to stabilize the air/fuel mixture and to pump additional air into the exhaust system to...

Q: My car has several misfire codes and does not run properly.

Hi there. What prompted you to replace those particular parts? Did testing reveal a fault? This year model, along with its sister IS models, up to 2011 had a service campaign for cylinder misfires. The campaign did not cover the...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
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...