help troubleshooting AC
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Cross-Country
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help troubleshooting AC
my parents 2003 5.4L super crew has a very weak AC. Even with AC Max on and temp/blowerspeed on the highest setting, it is at best a little cooler than a fan blowing "cool" air. I bought an AC Pro 134a refrigerant refill bottle with the gauge/needle. After turning on the truck(to operating temp) and turning on max AC and setting the fan speed and temp to the highest/coolest setting, the bottle's gauge measured in the yellow section. The yellow section is supposed to indicate that there is enough refrigerant. The compressor kicks in right away, so I'm assuming that isn't the problem either. Any thoughts? Of course I would take it to a tech, but we are first trying to solve other problems. Thanks in advance!
Hotshot
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the compressor should kick in and run up to 30 seconds, then kick off for 10 seconds, then kick back on... etc.... What happens is the pressure in the low and high sides is STABLE at something like 100 psi.... compressor starts and starts sucking down the suction side ... that should be 35-40 psi or so ( depending on the ambient temp).... if the pressure falls to about 20 psi, then the low pressure switch opens and the pump kicks out... the pressure then starts to stabalize and when it gets to about 40 psi, the pump kicks back in and starts sucking down again.... If your ON time is too short, then you need more R134... If it NEVER kicks off you might be OK, or might have a bit too much R134.. Instead of going by YELLOW - GREEN... would be nice to know the pressures value.............. i assume there was SOME PRESSURE in the line when you started adding R134..... If it every goes EMPTY, then you have a possibility of getting air into the system.
also get a garden hose and flush out the fins on the radiator and air conditioner coil... dirt / bugs / oil, make a BIG difference in cooling.
also get a garden hose and flush out the fins on the radiator and air conditioner coil... dirt / bugs / oil, make a BIG difference in cooling.
Hotshot
Joined: Jul 2005
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is the YELLOW area pressure less than the GREEN ? If so, i would guess you need MORE R134.... the AMBIENT temp is important when determining the needed PRESSURE... You can also stick a thermometer in the dash vent and record the temp... GREAT is below 50 degrees... 55-60 is OK for an old truck with some wear... If you cant get below 60 degrees, then you have some problem.
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Cross-Country
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as far as the compressor goes, I know it does kick in. However, I do not remember if and how often it turns off. I will also ask my dad if he has had anyone "top it off" recently. I believe they haven't taken to anyone in a few years and that was to top it off, but it wasn't any help, as far as I remember. I thought about using a garden hose on the radiator and air conditioner coil but was unsure. I might give that a shot.
Fleet Owner
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Cross-Country
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Thanks. I'll have to check those.
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tealboy1
1997 - 2006 Expedition & Navigator
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Sep 28, 2003 11:32 PM
