Air Conditioning

[cjim730]

My 2000 Silverado 4.8L 300,000 miles , air conditioner cools great in the driveway, but will only cool for about 5 minutes when moving . I replaced the o ring/gaskets on the firewall (they leaked), replaced the orifice tube (it was dirty) and then had the system evacuated, re-charged, and tested for refrigerant leaks by a professional. Like I said, worked great in the driveway, but as soon as I drive in no longer cools. What causes the system to do this?

[Jsdirt]

Take a look in front of, & in between the condenser & radiator for debris. Make sure it's clean. Once that's done, my best internet guess would be air in the system causing pressures to activate the hi pressure cut off, or a faulty HPCO. Some other things could be excessive moisture in the system, due to saturated (read not replaced during service) accumulator desiccant, causing the orfice to freeze. Could also be a low charge as well. Need to have a look with gauges to really know for sure.

[cjim730]

Take a look in front of, & in between the condenser & radiator for debris. Make sure it's clean. Once that's done, my best internet guess would be air in the system causing pressures to activate the hi pressure cut off, or a faulty HPCO. Some other things could be excessive moisture in the system, due to saturated (read not replaced during service) accumulator desiccant, causing the orfice to freeze. Could also be a low charge as well. Need to have a look with gauges to really know for sure.

 

Thanks for the reply. I know there is not any debris near the condenser or radiator. I keep my engine very very clean. I will have the system evacuated and recharged again. Hopefully that will do the trick. I was just hoping for some quick and easy miracle solution.