i have a 2000 blazer 4.3 vortec. a/c won't get cold. compressor doesn't make any unusual noise. checked the "charge" it was low. i used a can of refridgerant, still no cold air. checked later, charge was low again. where do i start troubleshooting? any tips would help alot. thanx.

 

Take and get the U.V. kit at the parts store put that in the system and then following the directions check for leaks!! The kit comes with a special light and glasses for tracking down leaks.

 

The compressor will only run about 5 seconds at a time until it has enough gas pressure in the system.

 

Yeah, and if it's leaking, it's leaking oil with it because the refrigerant and the oil are miscible. So you might not have enough oil in there as well. Might be time to take that system apart for a good cleaning, flush, new o-rings, etc. if you want to do it right. Oh, and if you do you HAVE to vacuum the system down before filling, unless you want to replace the whole system soonafter.

 

have your whole system evacuated!!! and refilled properly..