Skip the auto shop - Our mechanics make house calls

Q: Car blows cold air

asked by on

Car blows cold air.. it blows a little warm air when fanot is turn on low but blows straight cold air when turn on high.. coolant is full. Doesn't leak when driving but when its parks for a couple hours it starts leaking a little. What could be wrong.. I changed my water pump a couple months back. And my oil is good.. please help

My car has 200000 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!

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: Tapping sound

Hello there, many components will cause a tapping noise with your 2003 Cadillac DeVille. The most common cause of a tapping noise is the fuel injectors. Injectors tap when they open and close and this is a normal operation. If...

Q: Car won't start after security system malfunction.

With your vehicle it is possible that there may be a fault in your security system that is not allowing your truck to start. There may be a fault code stored in the computer of your truck that may help...

Q: Is it possible to change autoride air shocks from factory to conventional shock absorbers? 2005 Cadillac Escalade

Hello - yes, it is possible, and indeed a common modification, to swap out the air ride suspension on this model for conventional suspension. In fact, several auto suspension suppliers make conversion kits to do just this. As you have...

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...
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.