Air Conditioning Questions

[OldPete]

2006 Chevy Silverado 1500 W/T. V6, Standard Cab, Full Bed

Got in truck today... AC not working like it should.

Diagnostics:

Engine running all HVAC off (fan off, everything off): Compressor does not run.

Engine running, fan on, recirculation on, AC OFF: Compressor cycles on for about 4 seconds and turns off -- stays off for about 30 seconds (+/-) and runs for 4 seconds

Engine running, fan on, recirculation on, AC ON: Compressor cycles on for about 4 seconds and turns off -- stays off for about 30 seconds (+/-) and runs for 4 seconds

I hear and feel relay working (which makes sense since the compressor is going on and off.

Air is not cool or cold.

Thoughts? I have a set of gauges and plenty of R22... if it's an R22 vehicle (I didn't even bother to look before I posted here).

Outside Temp: 91f.

Sure appreciate any help with diagnostics!

Thanks,
Pete

[LeoS41280]

Low on refrigerant. It is not an R 22 system. It uses R 134a.

[OldPete]

Thank you! I'l get the gauges on it and see what's doin'.

[pendragon]

Yup low on refrigerant, but the fact that it cycles on for a short while suggests that there is still some left, so wherever the leak is it might by very small

[gmtech4]

gauges ,smauges ,,,,,take it to a shop and recover ,and put it required amount and have them install some dye ,,,,,go back end summer for a a look with black light ,,,,do not do this ,let a shop ,you're wasting your time

[pendragon]

gauges ,smauges ,,,,,take it to a shop and recover ,and put it required amount and have them install some dye ,,,,,go back end summer for a a look with black light ,,,,do not do this ,let a shop ,you're wasting your time

No do not do this yourself, the amount of refrigerant in the system needs to be carefully measured, otherwise the head pressure will be to high or the evaporator pressure will be too low which will lead to icing up and no airflow

[chipjumper]

Like the others have said, take it to a shop if you don't have the proper toys. BUT it appears to be a tad low if the compressor kicks on at all. Advance Auto Parts sells leak detector dye in direct "shot" cans that you press on the low side (blue) port for three seconds. It injects ultraviolet dye into the system. Then I would dump in a 12oz can of R-134a freon. I wouldn't go more than 10-12oz. Feel free to buy one of those cans with the preattached hose. Then drive it as usual and inspect for leaks. You can see the dye without a UV light BUT using a UV flashlight makes the dye stand out strongly. You obviously have a leak - the missing R-134a went somewhere. Theoretically it could be several other things but most likely you have a small leak somewhere. Maybe even the high pressure port -- something that a pro should change out due to the evacuation procedure. Good luck!