Skip the auto shop - Our mechanics make house calls

Q: The heater isn't working right.

asked by on

The heater takes to long to START to get warm. Then it will stay warm for a few seconds. Then gets cold again. I'll turn it back off for a few seconds. Then turn it back on and it will be a little warm for a few seconds then gets cold again. This goes back and forth about 30 minutes and if I'm lucking it will finally stay warm. But sometimes it does take a little longer. Up until about 3 months ago it got warm right away and stayed warm. What part might it be and what can I expect it to cost. Thanks, Candy.

My car has 160000 miles.
My car has an automatic transmission.

Hi There, You may have a clogged heater core that may be prohibiting the outer linings of the heater core to get hot. As you know, the heater core is a series of tubes that the coolant runs through that generates the heat from the warm coolant after circulating through the motor. These tubes can occasionally develop a buildup on the inner walls such that when the heater core is "flushed" this buildup on the inner walls of the lines remains and still allows the coolant to flow through the heater core. It is important to note that when the heater core is "flushed" it is possible to get good flow through the heater core while the inside walls of the heater core remain caked with buildup. As a result, the buildup on the inner walls prevents the temperature from rising to its capability due to the insulating effect of this buildup on the inner walls which will prevent the necessary heat transfer to properly heat the inside of the car. I would recommend having an expert from YourMechanic come to your location to diagnose and replace your heater core.

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

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. The heater isn't working right.

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: How do I unlock the doors with the remote transmitter?

The remote transmitter key can be used to unlock your vehicle from the outside. To unlock the driver’s door, press the unlock button on the transmitter. When you use this function, some of the vehicle’s exterior lights will flash to...

Q: Speedometer quit working

The speedometer operates in correspondence to the speed sensor on the transmission. If all the other gauges are working on the dash then I would start by looking at the speed sensor on the transmission. The sensor generates a signal...

Q: Honda Civic 2007 oil indicator lamp issue

Simply put, since the light did go off after you started the engine, you are fine. Let me explain a little bit about your warning lights. When you turn your key on, all of the lights illuminate during the computer's...

Related articles

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...
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.