73-87chevytrucks.com
General Site Info => General Discussion => Topic started by: Irish_Alley on June 13, 2018, 11:46:29 PM
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Ok so this year was the first year I had to recharge the AC system in the 02. Went to add a can and right when it is almost full to turn the AC on it starts blowing in all back out of a leak around the compressor. Long story short I found the high pressure switch on the back of the compressor was snapped in two and the freon was just going through that hole when the clutch cycled on. This was the first time I heard of this and ever saw it. So I replaced the switch and the AC is working fine again, I think this was last week.
Anyway sister in-law was picking my boy up from school today and they heard air leaking out to the point her a a cop that was around thought it was a tire. But the tires weren't low when I got home I looked at the tires and knew that wasn't the issue and went straight to the compressor and the switch is broken in two again. Almost as if the compressor is building up too much pressure and blowing it apart. I may be 100% wrong but shouldn't the high pressure switch kill the AC if it got too high?
At this point I'm thinking new compressor but then I thought what if the orifice tube is clogged or something simple but I don't know where to start. Any ideas?
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Did you just add refrigerant or did you check your high and low side pressures? If the compressor is popping the blow off valve then obviously it is building pressure. Fans working? Condenser clear and unobstructed? Proper system charge?
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::) well not exactly proper recharge, i didnt vacuum the system out or anything like that. it only took 1 small can (what 12oz???) and it turned on half way of dumping that. didnt check the high side because i was hoping it was originally just a blow seal. then found the sensor and was hoping the first sensor was just faulty and broke. but after this second sensor blew off i now know its a system issue.
i dont even have a proper gauge to test the high side but like you said theres no real reason to check it because it blew the sensor apart.
fans im not sure, cant really even tell you if it has any accessory fans but the main one is a clutch and havnt noticed any issues with running hot.
ill check the condenser tonight when i get home along with the fans.
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well had it working for a few weeks till it just stopped on me a couple days ago. still dont have a high pressure gauge but the compressor kicks on and the low side is in proper range. but it blows nothing but warm air. the ac lines dont really get cold like i think they should and the idle of the truck is really low around 400 rpms to the point on when the ac worked you would have to raise it to 700-1000
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Anyone who wants to work on their AC system NEEDS to have manifold gauges. Without them you are wasting time and money and would be better off taking it somewhere. You can buy inexpensive gauges online but even still you need a license to buy refrigerant and need many more special tools to do the job right.
sounds like you overcharged the system and also have a leak.
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not sure how it was overfilled, ill get the manifold gauges. but i know with the rpms at idle (around 400) the pressure is in the green if you start to increase the rpms the pressure will drop, then once you get above 1100 rpms the pressure will go into the yellow and then will go too low and the compressor will kick off for a few seconds then turn on and will cycle ever 5 or so seconds
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Without knowing low side and high side pressures you can't accurately diagnose it. If you didn't overcharge it then it sounds like the high side pressure rose above blow off
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If your low-side pressure was low and your high-side pressure was high, then you have some blockage in the system; probably at the orifice valve.
This is one of the reasons why you can't just buy a can of refrigerant and a single gauge at the low-side.
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rookie mistake lol. i redid my ac on my 94 years ago with only a low gauge, its still going strong today and is one of my coldest units. i did just replace the orifice tube last week due to the high pressure switch being blow out. it had some metal and "dirt" in it, one could assume it wasnt good and was the cause of the blockage. now with the issue im having now im kind of thinking the compressor is bad but want to make sure. the manifold gauge set is being delivered today so maybe tonight or tomorrow ill have a better idea on whats going on in the system
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ok here they are, starting with idle then about 1200-1500 rpms then about 2k. if i go above 2k im guessing the low pressure drops too low and it shuts off the compressor
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also note this was with a warm engine and ambient temp about 80ish. when i took the high pressure cap off it was leaking a little but once i plugged in the female side of the gauge and removed it the leaking had stopped. also no matter what rpms its at its only blowing warm/hot air. the low pressure side lines arnt even cold to the touch. the compressor does make some noise.
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Hook the center hose up to your source tank. Make sure the valves are closed. Open the source tank, and crack open the low side with it running to draw in more refrigerant. Continue to do so until the high side stabilizes around 210° at 80°
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Just to be clear you mean 210 PSI at 80°? I added a small can and part of another the high side is around 155 low side about 50. The low side now is getting colder, could still add a can should I be concerned about the low side pressure or will that drop when the high side gets around 200?
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Add more refrigerant. If it's cooler than 80° when you are doing so the pressure will be lower. Refer to the temperature pressure chart, here's one you can reference:
http://rechargeac.com/how-to/ac-system-pressure-chart
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also vile can you please explain the gauge for me. more so the wet/dry view finder in the center
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A site glass is pretty much irrelevant when you have pressure gauges. It's for the I need to see it kinda guy.
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so i added 24+ oz of freon, the truck from what i can find online calls for 29oz. i added 2 12oz cans and part of another not sure how much but i imagine it was somewhere between 4-6. cant get the high side to go above 150 and the low side is around 50-60. the low side at idle is around 70 and the high is around 125 BUT idle is still low (around 500) give her some gas and thats when the high side goes to 150 and low starts dropping. temp somewhere between 75-80 which might be why i couldnt get it to reach 200. but the ac does blow cold now as long as youre moving but stopped or idle it warms right up and the low pressure hoses are cold now. so its back to the way it was before the high pressure switch blowing out
so i want to fix my low idle and im thinking it has to do with the fuel pressure, maybe the fuel pump. it has a hard time starting when cold. it has to rotate longer than it should to start and then it sounds like it has a miss. if you shut it off and restart it it runs fine. i just replaced the intake gasket for it leaking and swapped out the MAF with a known good one. havnt touched the fuel pressure reg. i did look at it as i was told a sign of a bad one would be that its leaking fuel and mine was dry, with code P0171, P0174
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Sounds like the compressor is ready for retirement
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Also here is the pressure chart for your truck. Keep it handy for when you do fix it