98 5.7L Suburban 2WD Vortec - AC Issue. PLEASE HELP
 

Brand new Fan clutch. Brand new fan on the fan clutch. Blows cold when driving. Stopping only blows cool.
Have cold lines on one side of main assembly. Have hot side on the other. Compressor clutch always engaged but I think that is normal on these vehicles. In other words it's always spinning on front of compressor.

I haven't checked the orifice tube, but could that even be a symptom?

It's 82 in Texas tonight. I got pressure right on the money according to the gauge.

What else can I check? Someone suggested put a leaf blower to the front of the truck and see if the AC is cold at idle then..... I'm at a loss.

HELP

Re: 98 5.7L Suburban 2WD Vortec - AC Issue. PLEASE HELP
 

Sounds like it's a tired compressor or low on freon.

Re: 98 5.7L Suburban 2WD Vortec - AC Issue. PLEASE HELP
 

Making the assumption of what you said is correct.

Compressor should be cycling on and off. If it's constantly running there is probably an issue with your high pressure switch located at the accumulator.

If it's not shutting off, it will over cool and your evaporator will freeze causing the air coming from the vents to warm up.

You can test both the switch and the theory of freezing due to running too much. The switch is obvious. You can unplug the wires while it's running to see if cycling the clutch causes the cooling to return to normal.

Good luck

Re: 98 5.7L Suburban 2WD Vortec - AC Issue. PLEASE HELP
 

There are 3 switches for the AC system. One on the dryer. One on the back of the compressor and one on top of the compressor.

Your saying the one on the dryer.... but I thought that was the low pressure switch. Isn't the high pressure switch on the back of the compressor?

Thanks

Re: 98 5.7L Suburban 2WD Vortec - AC Issue. PLEASE HELP
 

I unplugged the switch on the accumulator and the compressor clutch stopped. It never came back on. I unplugged the one on the back of the compressor and same thing. The clutch never engaged. Plug either one back in and clutch comes on and stays on. It never stops.

Re: 98 5.7L Suburban 2WD Vortec - AC Issue. PLEASE HELP
 

Dirty evaporator core? Recently saw someone fix an slight overheating problem by removing the radiator and oil coolers and pressured washed them. Lowered his temps 20 degrees I think it was.

Evaporator core is up front so it catches most of the dirt and bugs.

Re: 98 5.7L Suburban 2WD Vortec - AC Issue. PLEASE HELP
 

:confused: That would be the condenser coil. The evaporator core is inside the cab.

The switch you want to focus on is on the accumulator. It has a screw inside it. It's adjustable. You unplugged it and it stopped, you plugged it in and it engaged. Keep going, you're almost there.

So I replaced the compressor. I vacd everything out. I got it up to 64 ounces of freon. Compressor clutch still comes on and stays on. All switches are brand new just replaced.

My only question is ... I can't get the low side pressure below 60-70 psi and 210/220 on the high side.
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Re: 98 5.7L Suburban 2WD Vortec - AC Issue. PLEASE HELP
 

Do you guys think a plugged condenser would cause my pressure to be so high?