Skip the auto shop - Our mechanics make house calls

Q: Heater only works sometimes

asked by on

Ok so here's the deal I let my car run and warm up until my thermostats says it's warm I turn the fan on I get cold air but when I put the air to the from vents I get warmish air. Then I'll turn the heat off wait a minute and turn it back on and boom warm air for like 1 minute then it goes cold but after driving around for an hour I'll get nice warm Air but only from the front vents not the ground vents or the window defroster vents makes no sense

My car has 280000 miles.
My car has an automatic transmission.

The lack of heat being generated by your system may indicate a clogged heater core. 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
  1. Home
  2. Questions
  3. Heater only works sometimes

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: There is fluid that looks like a chocolate milkshake in the radiator

This is generally a sign of a blown cylinder head gasket. When the cylinder head gasket is compromised, this allows oil to leak into the coolant system, creating the chocolate-like substance that you see in the radiator. When this happens,...

Q: Having issue with HVAC system in my car

This symptom can actually be caused by two different things. You are right to think that the blend door actuator could be at fault. If the blend door is not able to move, this will not allow air passing over...

Q: Bad shifter cable. 2002 Lexus ES300

Hi there. When it comes to a vehicle getting in an accident and having issues with other components, this is a common problem that cannot be avoided at times. When the vehicle was looked at and quoted, the problem was...

Related articles

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...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.