Q: While driving defroster set to hot blows hot air as it should, while idling it is blowing cold air.

asked by on

While driving defroster set to hot blows hot air as it should, while idling it is blowing cold air. When I stop at a light the air almost immediately becomes colder, as I accelerate the air begins to get warmer, seems to take longer to switch from cold to hot than it does to switch from hot to cold. There is no change in fan speed. The car never did this before.

My car has 108000 miles.
My car has a manual transmission.

First, the coolant level should be checked to make sure the radiator is full. While the overflow tank may be full, the radiator cap must be taken off to check the level inside the radiator. If you find the level is very low, you have a coolant leak that must be fixed. If coolant levels are normal, an engine thermostat or heater control problem may be what you’re experiencing. Consider hiring an experienced technician like one from YourMechanic who can come out and take a closer look at your lack of heat concern to offer a more personal diagnosis.

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. While driving defroster set to hot blows hot air as it should, while idling it is blowing cold air.

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: Sky slider not closing properly

The sky slider feature not closing properly on your Jeep Liberty is actually not an uncommon problem. There is actually a technical service bulletin that informs certified mechanics on the proper fix for this exact problem. In most cases this...

Q: rear end problem

Hi there. Unfortunately, we do not have the type of information readily available to answer this type of question. We can assist you with any question that involves returning a vehicle to factory specifications; we cannot provide modification information. Your...

Q: ABS shuts down transmission

Check to be sure the transmission has adequate fluid. Too little fluid and the car won't move. The ABS system electronics, and the braking control that the ABS pump provides, do not have any connection to the transmission. If multiple...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
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...
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.