Car heater blowing cold air even with good coolant and thermostat
Car heaters can blow lukewarm or cool air despite having normal coolant levels and a working thermostat. This leaves drivers with weak or no heat coming from the vents when turning the system on full tilt.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Manually manipulating the blend door actuator arm to get temporary warmth.
- 2Flushing or backflushing the heater core
- 3Replacing the thermostat
- 4Manually manipulating the blend door actuator arm
- 5Manual manipulation of the blend door actuator arm to get temporary lukewarm air.
- 6Use a DIY refrigerant recharge can with a pressure gauge
- 7Take the car to a shop to run an AC leak and dye test
- 8checking fuses and relays
- 9checking for power with a multimeter
- 10jumping 12v to confirm the clutch works
- 11checking refrigerant levels
- 12checking fault codes
- 13replacing blend door actuators
- 14Checking temperature gauge
- 15Checking compressor pulley spinning
- 16Going to a mechanic for diagnosis
In their words
Unedited, most upvoted first, each linked to the thread it came from.
“Now it dosen' t work. Or I dos work but only blow hot air. Is et normalt to go a year and den stop working? I have jused it from now til august This year!”source ↗
“I have a 2010 Kia forte Koup 2.4L with about 200k miles on it with very weak/no heat from the vents.”source ↗
“If I turn the heat on full tilt, I get at best lukewarm air, or at worst cool air.”source ↗
“I have a 2010 Kia forte Koup 2.4L with about 200k miles on it with very weak/no heat from the vents.”source ↗
“If I turn the heat on full tilt, I get at best lukewarm air, or at worst cool air.”source ↗
“Pontiac g5 2008 blowing hot air from /c vents.”source ↗
“whenever I turn the dials to hot it just continues to blow cold air (ac cold air 😂) the temperature gauge has no problems and the car consistently drives at the right temp , my coolant is full , just no hot air … any advice ?”source ↗
“I have a 2010 Kia forte Koup 2.4L with about 200k miles on it with very weak/no heat from the vents.”source ↗
“If I turn the heat on full tilt, I get at best lukewarm air, or at worst cool air.”source ↗
“Two days ago when I went to leave for work, the AC was blowing warm air.”source ↗
Where this came up
People with this problem also raised
- 3Why is my AC blowing warm air?
- 2AC unit humming with no air coming out of vents
- 2Why does my car AC stop working when it's really hot outside?
- 2Why is cold air blowing out of my AC drain line?
- 3Why does my HVAC fan run continuously and blow hot air?
- 10Why does my brand new AC not cool as well as the old one?