The car has a new radiator and water pump, I just changed the coolant about two months ago. The air coming out of the vents is barely warm, not hot like it used to be. What could be the issue?

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    Did you change out the thermostat? Dec 22, 2016 at 16:00
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    Was the system correctly burped? There may still be air in there.
    – PeteCon
    Dec 22, 2016 at 16:40
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    How about the heater hoses? At operating temperature both should be hot to the touch. If one is hot and the other is only warm or cold, flush the heater core.
    – Ben
    Dec 22, 2016 at 22:32

2 Answers 2


Chris Fix has a great series of videos on how to troubleshoot and fix this issue



The A/C systems in cars are very complex. With the car's cooling system working the control that regulates the temperature is suspect. The only way to repair this is to have a professional mechanic troubleshoot the system. But the first step should be to test the operating temperature of the cooling system. Equipment is required since most cars do not have temp gauges. I have an app and an ODD-2 transmitter that allows data to be read. The second suspect, depending on the age of the car, is the heat exchanger, a type of radiator, that can be deficient. Guessing is not wise. Good luck.

  • another non-helpful answer with generic suggestions, some of which are totally irrelevant. Are we sure this user is not a bot?
    – rviertel
    Dec 23, 2016 at 0:46

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