How Does A/c Make Temp Rise??

Grabbin' Asphalt

5 Year Member
Jun 10, 2013
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Atlanta, Ga
Curious, I know the a/c condensor is near the radiator, but as it gets hot along with the fan trying to cool both it and the radiator, is this the only reason temps rise?? I think the computer pulls a little timing out when running the a/c but is the main reason??
 
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Load on the engine increases, but the main contributor is the condensor sitting in front of the radiator. Drawing hotter air through the radiator won't make it cool as effective.

Also, sitting in traffic will heat soak the engine bay much more than being on the highway. Mustangs are pretty bad when it comes to heat soak affecting how they run.
 
To put more texture on it, the A/C compresses the refrigerant, puts it through the evaporator core, where the refrigerant boils and absorbs heat from the interior. Then it's taken to the condenser where it's reliquified, transferring the heat to the outside of the car...right in front of the radiator. Now the radiator, instead of having ambient air temperature to cool the engine, has ambient air + 40 or 50 degrees. To the radiator, it's like the day just got a lot hotter.
 
Yes, it is heat energy from the heat transfer (transferred from your car's interior and your personal exterior to the coil outside) plus the work of the heat transfer process being put right in front of the radiator that makes the radiator get warmer air and work like it is a hotter day. Can I make a longer, more specific sentence?

More outside temp air is the best answer, and stop and go traffic on hot days is the only reason I might consider an electric fan conversion. You can get good airflow at 0 MPH and idle. That it might free up some power is not bad either, but for reliability, I like a thermal mechanical fan clutch most of the time.
 
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Yes, it is heat energy from the heat transfer (transferred from your car's interior and your personal exterior to the coil outside) plus the work of the heat transfer process being put right in front of the radiator that makes the radiator get warmer air and work like it is a hotter day. Can I make a longer, more specific sentence?

More outside temp air is the best answer, and stop and go traffic on hot days is the only reason I might consider an electric fan conversion. You can get good airflow at 0 MPH and idle. That it might free up some power is not bad either, but for reliability, I like a thermal mechanical fan clutch most of the time.

I agree, nothing beats the simplicity and reliability of the fan clutch. The E fan produces nearly no power, you are still turning the water pump. I know people love it, but in most cases with quality parts, it's a poor bang per buck mod.
I've always thought of putting a pusher fan on the AC condensor for poor AC performance in traffic.
 
I have seen magazine dyno tests saying the electric fan switch is worth a few HP, but the alternator still has to produce the power to turn the electric fan. It seems like any HP savings would be at high RPM when the electric fan goes the same speed and the clutch fan is working harder.