Q: A/c blowing cold air intermittently with warm air
My car has around 158,000 miles.The air conditioner blows both cool and warm air. What is causing this and what is the solution. Thanks.
Recommended Services
| AC is not working Inspection | $111.46 - $131.46 | Get a Quote |
Hello. If the system continually blows hot and then cold, this is typically caused by a failing blend door actuator. If it fails, it can allow the temperature door to not hold the right position. It can also be caused by a bad metering valve or a compressor issue.
I typically start by checking the pressures in the AC system just to make sure that the system is functioning as it should. If it is, then I move to the doors under the dash to see if it is one of them not working properly, or if it is a failure in the control unit. If you need to have this repaired, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose your AC system and perform any services that are needed.
The statements expressed above are only for informational purposes and should be independently verified. Please see our
terms of service
for more details
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
What others are asking
Engine won't start.
You should get your 'no start' inspected (https://www.yourmechanic.com/services/car-is-not-starting-inspection) by a qualified technician. The most common problem on this vehicle for a 'no start' is the fuel pump and filter. The fuel pressure will have to be checked by a certified...
How do I delete a paired phone?
If you are no longer going to use a phone with the Bluetooth system, you should delete the pairing. To do so only takes a few steps: 1. Press the Setup button. 2. Rotate the Tune-Scroll knob to Bluetooth, then...
Battery dead after a few days
Thanks for writing in about your Mercedes Benz CLK430. This is a common problem as vehicles get older. This type of fault is called a parasitic draw and occurs when one or more component does not shut off when the...
Feels like small vibration or humming from front drivers wheel
You may have a tire that is defective or has a stop leak - this could be causing the vibrating hum problem. You should have the tires checked and rotated to see if the problem moves with the tires to...
Jerking reaction when accelerating
This may be related to a faulty throttle position sensor or potentially a dirty or failing mass air flow sensor (https://www.yourmechanic.com/services/mass-airflow-sensor-replacement). The mass air flow sensor is a unit in the intake system that monitors air intake as it is...
I have a 2009 chevy Aveo, and my temperature gauge is below the cold line. It my heat is blowing out semi warm.
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...
Heat works okay on low fan but gets cold on higher fan speeds
The heater core fins are blocked with dirt, hair, debris from inside and outside air and will not let enough transfer of heat to the air. Core may need to be replaced. The temperature control actuator may not be moving...
Can you please assist me regarding my ford bantam 2004 model 1.3 xi. It does not start when its raining or partly cloudy.
Hi there. Usually electrical issues are common when it is wet out. I recommend replacing the spark plugs as they are not producing enough spark for added moisture in the atmosphere. Then check all of the ground wires to the...
TRANSMISSION PROBLEM
Hi There, What you are describing sounds like possibly low transmission fluid (https://www.yourmechanic.com/services/transmission-fluid-service) or a bad speed sensor or potentially a faulty transmission control module, which also controls the speed sensors. The transmission control module has various sensors such as...
Related articles
What Causes the AC System to Leak?
Your car’s air conditioner is responsible for keeping the interior cool and comfortable on hot days. However, in order to do that,...
How Long Does an AC Accumulator Last?
Your Your vehicle’s air conditioning system is a complex system of components, each of which plays an important role. However, not all the components will continue to work properly if they come into contact with moisture, and that is where...
How Long Does an AC Control Module Last?
Over Over the past decade, vehicles have become far more electronic than they are mechanical, with numerous computers on board that control various functions. Your AC control module is one such computer, and it works to manage the air conditioning...
Browse other content
Services
Estimates
Maintenance