A/C not working at idle
06-02-2010, 05:33 PM
#15
Jan 2008 TOTM & Gdreject
I used a 16 inch fan I believe. I ran a wire inside to a switch in my cab. Eventually Iwill run a relay and tap into an ignition wire so it kicks on regardless
06-02-2010, 05:37 PM
#16
Moderator (Ret.)
I also noticed this same post was placed on another forum.
If you want to go the route of an e-fan, just go all the way and replace the clutch fan with that of a total electric fan setup. Kits can be costly, but you can buy a used Mark VIII electric fan and a DC Controller all for under $150.00. You'll remove drag off of the engine as a bonus.
There was a geat pictorial post on this forum a little over a month ago.
So, your A/C will work better at idle, plus you can remove drag off your engine. Some will chime in and say it will improve (slightly) gas mileage.
Again, low cooling A/C at idle is normal on our trucks; more so with the 5.4 engines. Comes up as a topic every year at this time of year. Checking the freon is always a good idea, but you'll see that the cooling efficiancy is low during idle, especially during the daytime heat. You may notice that during the winter when the defrost was used in your vehicle, the engineers made it so the A/C compressor cycled on. This was for two reasons; one to make the defrost work quicker, and two, to keep the seals in the A/C system from drying out and causing the freon to leak.
The primary reason for low A/C efficiency at idle is that the clutch type stock fan simply does not pull enough air through the grill to cool down the condensor. If you were to hold the engine at a higher rev, or place another fan in front of the condensor (as the other poster did), your A/C will cool better at idle. The principle of auto A/C is not to "cool" the air, but rather it removes heat from the air that's circulated in the cab. Freon is compressed from a liquid to a gas, heat is removed from the air, then the gas converts back to a liquid. This is the cycle that takes place to remove heat, making the air cooler. R134 freon required a much larger condensor to work as good as R12 did, and requires more area (surface) to be cooled in order to be efficient.
If you want to go the route of an e-fan, just go all the way and replace the clutch fan with that of a total electric fan setup. Kits can be costly, but you can buy a used Mark VIII electric fan and a DC Controller all for under $150.00. You'll remove drag off of the engine as a bonus.
There was a geat pictorial post on this forum a little over a month ago.
So, your A/C will work better at idle, plus you can remove drag off your engine. Some will chime in and say it will improve (slightly) gas mileage.
Again, low cooling A/C at idle is normal on our trucks; more so with the 5.4 engines. Comes up as a topic every year at this time of year. Checking the freon is always a good idea, but you'll see that the cooling efficiancy is low during idle, especially during the daytime heat. You may notice that during the winter when the defrost was used in your vehicle, the engineers made it so the A/C compressor cycled on. This was for two reasons; one to make the defrost work quicker, and two, to keep the seals in the A/C system from drying out and causing the freon to leak.
The primary reason for low A/C efficiency at idle is that the clutch type stock fan simply does not pull enough air through the grill to cool down the condensor. If you were to hold the engine at a higher rev, or place another fan in front of the condensor (as the other poster did), your A/C will cool better at idle. The principle of auto A/C is not to "cool" the air, but rather it removes heat from the air that's circulated in the cab. Freon is compressed from a liquid to a gas, heat is removed from the air, then the gas converts back to a liquid. This is the cycle that takes place to remove heat, making the air cooler. R134 freon required a much larger condensor to work as good as R12 did, and requires more area (surface) to be cooled in order to be efficient.
Last edited by Mod (Ret.); 06-02-2010 at 05:44 PM.
07-07-2010, 10:01 AM
#18
Moderator (Ret.)