Q: Heater gets hot but then blows cold when idling or driving.

asked by on

heat gets hot then cold when idle or driving i have changed thermastate and new coolant

My car has 45000 miles.
My car has an automatic transmission.

This may be due to a faulty heater blower motor or potentially a bad heater core. As you may know, the heater core 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. To avoid any unnecessary repairs, I would still recommend having a certified expert, like one from YourMechanic, come to your location to diagnose your heater issue firsthand and make the right repair.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Heater gets hot but then blows cold when idling or driving.

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: Q: Steering wheel feels loose

From the description provided, it appears your Isuzu may have damaged one or more of the components in its steering and suspension system. The vehicle may still be drivable, but I must emphasize that this does not mean it is...

Q: My car started overheating and I believe it was because of the coolant because I put some more and stopped

Hi...If there is an obvious leak, the fastest way to resolve this is to request a leak diagnostic. If simply "one" leak point is found on inspection, the responding certified mechanic will simply identify the parts required to fix it...

Q: Car won't start replaced timing belt cam shaft and crank sensors still get p0335 amen p0340 code

The codes suggest an electrical (wiring) and or sensor fault. A real time scanner can graph sensor function on cranking and you can obtain that diagnostic if you request a check engine light diagnostic. P0335 can set if any of...

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...
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.