Automotive Air Conditioning Information Forum (Archives)

Smitty on Tue August 12, 2014 8:05 PM

Year: 2000
Make: Chevrolet
Model: Silverado
Engine Size: 5.3L
Refrigerant Type: R134a
Ambient Temp: 90-100
Country of Origin: United States

Hello, I have a 2000 Chevy Silverado 1500 4x2 with a 5.3L engine and automatic transmission. It has 206K miles on it and the AC has never had any work done to it. Lately, the AC will quit blowing cold, fan still blowing. Sometimes it will blow cold for well over an hour while driving then quits blowing cold but will resume blowing cold after a minute or so. Other times I will have to turn the AC off for a while, 5 to 10 minutes, and then when I turn the AC back on it blows colds again. The latter seems to be the case when it is hotter outside. I also noticed the compressor, or maybe it is the clutch, seems to be noisier (rattling sound) than it used to be when the engine is at idle and the AC is on. Any direction is greatly appreciated.

GM Tech on Tue August 12, 2014 9:53 PM

Extremely common complaint for your vehicle-- clutch driver is probably NOT engaged when it should be- due to a wide (worn) air gap- seen it dozens of times on those Nippondenso compressors- to prove it out- stop and see if front hub is turning next time it happens (gets hot inside) if it is not turning-tap front of compressor hub with a hammer handle-if clutch engages- you have the dreaded wide air gap issue---fix is to remove clutch driver hub and remove thickest shim from behind (against shaft)- then replace driver hub and make sure the driver does not rub the pulley face (air gap is not closed)- then you'll get another 80k miles out of it...

The tensioner rattle is another common issue-just do a forum search for tensioner rattle-- the answer for that one is a new compressor, new tensioner combination.

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

Smitty on Tue August 12, 2014 11:08 PM

Thanks for the help. I'll check it out. Thanks again.