A/C Cycles on and off

Vanlover · Post by **Vanlover** » Sat Oct 01, 2016 7:13 pm

Awesome forum here. Hoping to get some help. My 2002 Chevy express van ac compressor kicks on and off every 10 seconds or so. I bought a recharge kit with a gauge and pressure builds and then drops when it kicks on and off. I do not want to add anymore refrigerant until I know what's happening. Any ideas what may be causing this? Air blows but not cold. Thanks all.

GM Tech · Post by **GM Tech** » Sun Oct 02, 2016 5:51 am

That indeed is one of the symptoms of low refrigerant - you have a leak and are probably at about 15% refrigerant left in the system- best way to check is to have refrigerant extracted and weighed to know how much you have lost-- would just keep refilling a tire that goes flat once a week?

Vanlover · Post by **Vanlover** » Sun Oct 02, 2016 8:32 pm

GM Tech wrote:That indeed is one of the symptoms of low refrigerant - you have a leak and are probably at about 15% refrigerant left in the system- best way to check is to have refrigerant extracted and weighed to know how much you have lost-- would just keep refilling a tire that goes flat once a week?

I have added refrigerant but the air never got cold not even for a minute. Pressure gauge goes up then drops every 10seconds or so. Would that be a sign of a leak?

SingleMalt · Post by **SingleMalt** » Mon Oct 03, 2016 3:32 pm

Those recharge kits from the auto parts stores hook up to the low side port. You see the pressure drop when the compressor kicks in because the compressor is pumping the freon from the low side to the high side. And as GM Tech said, this rapid cycling is a sign of low refrigerant. Two possibilities:

1. The system has no leak and you didn't fill it up enough. (but then how did it get low?) Some of those older cars have mammoth R134a capacities - I just worked on an '04 Escalade that holds 43 oz of R134a. If I tried to fill up an almost empty AC system with a 16 oz can of refrigerant, you can see the problem. It's still not full.

2. More likely you have a leak. Need to fix that first, otherwise the leaky tire analogy applies.

Test for leaks with UV/dye or a sniffer. Before refilling, you need to vacuum it down anyway. If the system can't hold a vacuum, it for sure can't hold R134a under pressure.

Danielpat · Post by **Danielpat** » Sun Oct 30, 2016 6:27 pm

ok. the strange thing is that it hasnt done it before and it clicks a lot. also, the green light on the thermostat blinks when this is happening.