Air Conditioning starts stops
 

I have a 2000 Chevy Blazer LT with an AC problem
When you first start the truck it works fine for about 3 -5 minutes then starts blowing warmer air, does not want to take any additional 134r.


Any suggestions?

When it stops blowing cold air is the AC compressor pulley spinning?

Yes it is clutch is not

So, are you saying that the AC clutch is not engaged when it blows warm air?

If that is the case, there are several potential problems, ranging from an improper refrigerant charge, to a bad pressure sensor, to faulty wiring.

Do you by chance have access to a set of AC gauges? If you do, hook them up and see what your low side and high side pressures are with the AC running, and watch them when the clutch disengages.

These systems rely heavily on the amount of charge. If it's not within +/- 2 ounces of capacity, you will have problems. Checking pressures will not determine the level of charge. The only way to know how much refrigerant is in the system, is to drain, evacuate to 29.4" Hg for a minimum of one hour, and recharge with the proper amount of R134a refrigerant. Once that's done, post the high and low side pressures when the compressor starts, and when it stops running, (4 readings).

Does the compressor cycle on and off constantly? Mine did this and it was the pressure sensor in the Freon line going out. I took the plug off the sensor, jumpered it and found the AC would come on and run no issues.

This was after testing it had plenty of Freon of course. This was 110k miles ago.

Thanx for the info, after recent attempted top up with Johnsons sealant lube & 134r all in one can AC works for about 5 mins then blows warm air.
And that only happens when the truck sits for several hours.
Being in Canada 134r is only sold under license, so I will be ordering through ebay a can with pressure gauge. Planing on changing the actuator as I have lost floor heat as well.

you need ac in Canada?

I am responding just to be polite. Yesterday at one of our major highway intersections - 8 lanes east 8 lanes west four lanes north 4 lanes south the temperature was 99 F. -in Canuck 36C
So yes in Canada AC is desired EH.
I am looking for responses from people with at least a general knowledge.

Newguy responding to you was just joking around, do not take it seriously. We cant always be serious here, if we were we would lose our minds.