Engine Size: 3.0
Refrigerant Type: r134a
Country of Origin: United States
Bought my daughter a '94 ranger..nice truck, low mil 4x4 new paint..even has the A/C dealer retro fitted to the newer style-so I can use the stuff to recharge from my local shop myself...."just needs a charge'" uumm hmm. Charged it today and the compressor came on then off then on but started to blow some nice clod air. Then I hear pressure releasing ...looked and see everything going out the pressure relief valve on top of the compressor. Thought well maybe it had a charge and the low pressure switch is bad. I jumper'ed the switch and the compressor did come back on and stay on as long as the jumper wire was connected...after a minute pressure started coming out of the relief valve again and no more cold air...suggestions? New relief valve and low pressure switch? I only paid 2200 for the truck so want to stay cheap! taking it in won't be I am sure...
Pressure relief valves were suppose to be illegal in 1994 and replaced by a high pressure cutoff valve. Condenser should be a parallel flow and not a tube and fin. In any event, that relief valve should not kick open unless your high side pressure is exceeding around 430 psi. Memory tells me this is a CCOT system with a cycling switch on the low side. Needs around 45 psi to kick in, kicks out at around 25-30 psi.
You need a set of manifold gauges to post what is going on. Post a photo of your service ports if you want help. Should be R-134a ports, could be converted R-12 ports.
Ha, if you are paying for gas for your daughter like I was, got her a car that would at least get 37 mpg. Or can go broke keeping that tank full.
Have a good guy for insurance...I am up the creek with gas ;(. there is an orifice tube. I am thinking replace that and the low pressure switch....go from there. I guess I will lose the charge when changing the tube.....
I do not have a gauge and there was no motion across the condenser...I have heard that a clogged orifice tube could definitely cause this issue...
I assume I will need to have the system evacuated, change the tube, then have a vacuum put on the system....getting pricey already....
Over pressure occurs if there is not enough air going through the condenser. Also it could have air mixed with the refrigerant (because the last service did not properly evacuate it), or overcharged.
If you're going to work on A/C systems you at least need a gauge manifold with two gauges so you can see the high side pressure rather than waiting for the relief valve to pop.
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