Recently bought a 1999 Blazer, lovin it. Has a couple small issues, but the one I want to adress the most is the AC. It blows very well and very strong, but its blowing hot. I recharged the system yesterday and no luck. My mechanic friend says I should try and wait, that part where the low and high ports connect to and run through may still be filled with residue that needs to evaporate, he says. What are some common issues you guys have dealt with? I was thinking of changing the Ac compressor fuse next.

 

When you call for cooling does the compressor clutch engage and start spinning the compressor?

George

 

No, I can move it back and forth with my hand but when the ac is on (or trying to be) it doesn't spin at all

 

1. Is this manual or automatic climate control?
2. Do you have any manifold gauges and if so what is the static pressure with the system off?
3. We will check all the fuses as soon as you answer 1).

George

 

On my 99, I thought I had a leak but it turned out the expansion orifice tube got clogged with debris from the vanes in my pump deteriorating.

I figured out this was the case when I started my repair by venting the system expecting no refrigerant but instead finding it to have been fully pressurized.

I knew the pump was bad so at the minimum I knew I had to replace it and the expansion tube. Then I realized that to get all the debris out I would have to replace or flush everything.

I ended up replacing the following: the pump, hoses, expansion orifice tube, schrader valve, pressure switch, and condenser.

I was able to keep the heat exchanger and flush it in place.

I initially thought I could salvage the condenser but its passage ways were too narrow to flush.

I think the worst part if the job was the mess and hassle associated with draining and removing the radiator.

I borrowed all the tools to evacuate and recharge the system from a local Autozone. It went pretty well.

I did a write-up on it in my build thread.

 

When you recharged the system but no luck, did it empty one or two cans or did it not take any cans?

 

1. It is a manual climate control
2. No clue, Im going to find out this Thursday, the 18th

 

Sounds like a hassle. Im taking it to a shop after hours with my buddy to see what we can find, so thank you for leaving all this. Ill keep note of it when I finally get to work

 

We didn't put a full can in, we got to around 33-35 on the pressure gauge my recharge bottle came with then stopped. Wanted to see if it would maybe kick in a day or two later

 

That suction pressure is too low and is near the cut off for the low pressure switch. In 90° weather that should be over 50 psi and the pressure with the system off and equalized should be over 100 psi. Sometimes you can just keep adding cans of refrigerant and get lucky and get it to run but the only way to do it right is with a set of manifold gauges and a thermometer in the center discharge vent.

and if you really want to do it right you pressurize system with nitrogen to check for leaks then you pull a vacuum to 500 µm make sure it holds for 10 minutes, then weigh in the charge with a scale and a 30 pound cans of 134a to the charge weight on the face plate in the engine compartment. Then you monitor everything with high and low side pressure center vent temperature and ambient conditions before you call it good

George