A/C help-question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

80BIG10 · 06-07-2004, 02:36 PM

Ok guys....When driving and the A/C on I can hear my compressor(it is remanufacuted) cycling on and off. I can hear the clicking about every 3 seconds. I changed the LPV a couple of weeks ago and that seemed to help a little. I know I have a leak in the system but the pressure is close to 3lbs. Also, If I am in park the system does not cycle on and off. Is this normal? Is it going to hurt anything to leave the A/C on and it to continue to cycle on and off? Any fixes? I don't know if it makes a diffrence but it is a 350 4bbl. Any info would be great...Thanks.

NeCrOmAnCeR · 06-07-2004, 07:30 PM

Sounds like the system is low on refrigerant, or has a restriction in the orifice tube. Have you had a set of gauges on it to get a high and low side reading?? While not moving the condensor has a more difficult time condensing the refrigerant, thus the pressure remains higher on the low side and causes the clutch to cycle less.

80BIG10 · 06-08-2004, 06:43 PM

I have only checked the low side. I don't know much about the A/C system. Should both sides read 3lbs? Also, how good are the cans that claim to be leak sealers?

NeCrOmAnCeR · 06-08-2004, 10:45 PM

If the low side is only showing 3 lbs it is much to low. Is the system R12 or R134a? If R12, good luck trying to get a can of stop leak. I'd recommend having it converted when you find and fix the leaks. With the system running you would like to see the low side pressure around 25-50 lbs (depending on vent temp and outside air temp), and high side pressure around 220 lbs (again depending on ambient temp)
I'd also recomment not using the system until you get this problem fixed, with only a small amount of refrigerant in the system the oil is not being circulated very well and it will destroy the compressor.

80BIG10 · 06-09-2004, 06:54 AM

Im running the R134a. I will check it out. Thanks, for the help.

Pushrod · 07-10-2004, 12:17 AM

If you Freon is a little low and you don't want to add any and you compressor keeps cycling, pull the connector off the pressure switch and look in the center of your pressure switch and you will see a slot for a scredriver to fit in. turn it to the left 1/3 turn and it won't cycle on and off as much, re-install wire on pressure switch and road test it, this may help you some, it worked for me.

06-07-2004, 02:36 PM	#1
80BIG10 3 lefts make a right Join Date: Jun 2004 Location: Texas Hill Country Posts: 150	A/C help-question Ok guys....When driving and the A/C on I can hear my compressor(it is remanufacuted) cycling on and off. I can hear the clicking about every 3 seconds. I changed the LPV a couple of weeks ago and that seemed to help a little. I know I have a leak in the system but the pressure is close to 3lbs. Also, If I am in park the system does not cycle on and off. Is this normal? Is it going to hurt anything to leave the A/C on and it to continue to cycle on and off? Any fixes? I don't know if it makes a diffrence but it is a 350 4bbl. Any info would be great...Thanks.

06-07-2004, 07:30 PM	#2
NeCrOmAnCeR Registered User Join Date: Feb 2004 Location: Hodgenville, Ky Posts: 735	Sounds like the system is low on refrigerant, or has a restriction in the orifice tube. Have you had a set of gauges on it to get a high and low side reading?? While not moving the condensor has a more difficult time condensing the refrigerant, thus the pressure remains higher on the low side and causes the clutch to cycle less. Last edited by NeCrOmAnCeR; 06-07-2004 at 07:32 PM.

07-10-2004, 12:17 AM	#6
Pushrod Registered User Join Date: Jul 2004 Location: West Tennessee Posts: 19	Ac/help Question If you Freon is a little low and you don't want to add any and you compressor keeps cycling, pull the connector off the pressure switch and look in the center of your pressure switch and you will see a slot for a scredriver to fit in. turn it to the left 1/3 turn and it won't cycle on and off as much, re-install wire on pressure switch and road test it, this may help you some, it worked for me.

06-08-2004, 06:43 PM	#3
80BIG10 3 lefts make a right Join Date: Jun 2004 Location: Texas Hill Country Posts: 150	I have only checked the low side. I don't know much about the A/C system. Should both sides read 3lbs? Also, how good are the cans that claim to be leak sealers?

06-08-2004, 10:45 PM	#4
NeCrOmAnCeR Registered User Join Date: Feb 2004 Location: Hodgenville, Ky Posts: 735	If the low side is only showing 3 lbs it is much to low. Is the system R12 or R134a? If R12, good luck trying to get a can of stop leak. I'd recommend having it converted when you find and fix the leaks. With the system running you would like to see the low side pressure around 25-50 lbs (depending on vent temp and outside air temp), and high side pressure around 220 lbs (again depending on ambient temp) I'd also recomment not using the system until you get this problem fixed, with only a small amount of refrigerant in the system the oil is not being circulated very well and it will destroy the compressor.

06-09-2004, 06:54 AM	#5
80BIG10 3 lefts make a right Join Date: Jun 2004 Location: Texas Hill Country Posts: 150	Im running the R134a. I will check it out. Thanks, for the help.



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