A/C problems, and it's Damn hot
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Freshman User
Joined: Oct 2007
Posts: 28
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A/C problems, and it's Damn hot
I am having problems with my A/C, which is obvious from the post. I have used one of the part store meters to check my pressure level and it is a little higher than the meter says it needs to be, but when I check it the compressor cycles rapidly-every 5 seconds or so on and off- and it is only blowing mildly cold air. Any ideas about what I could check would be awesome. Also what pressure should I be running on the system.
is riding with me going it feels good in here
is riding with me going it feels good in here
Posting Guru
Joined: Apr 2004
Posts: 1,342
Likes: 0
From: Georgia
There is no pre-set pressure. It also depends on the ambient temp out in front of the grill. You will have to check the low side and the high side pressure to know what is going on. Here is a generic chart to show what I mean:
Ambient temp Low side psi High side psi
85* 45-55* 225-250*
90* 45-55* 250-270*
95* 50-55* 275-300*
100* 50-55* 315-325*
Using the chart and checking with a good gage (not the el cheapo), :
1) If low side is low and high side is low- add 1 can.
2) If low side is low and high side is high-usually blockage in the system like expansion valve or orafice tube.
3) If low side is high and high side is low-usually faulty valve in compressor (gages usually go nuts when this happens)
4) If low side is high and high side is high-overcharged system also resulting in a not so cold a/c. hope this helps your diagnosis.
Ambient temp Low side psi High side psi
85* 45-55* 225-250*
90* 45-55* 250-270*
95* 50-55* 275-300*
100* 50-55* 315-325*
Using the chart and checking with a good gage (not the el cheapo), :
1) If low side is low and high side is low- add 1 can.
2) If low side is low and high side is high-usually blockage in the system like expansion valve or orafice tube.
3) If low side is high and high side is low-usually faulty valve in compressor (gages usually go nuts when this happens)
4) If low side is high and high side is high-overcharged system also resulting in a not so cold a/c. hope this helps your diagnosis.
Fleet Mechanic
Joined: Jul 2005
Posts: 1,464
Likes: 103
From: Staten Island, NY
For a definite answer, more information is needed. What was the outside air temperature at the time and what were the high and low side pressures?
Judging by the rapid compressor cycling I'd have to guess that the system is low on charge. As a quick check, feel the low (suction side) hose just before the compressor. With the system running in max a/c and the engine at 1500 rpm or so the hose should be from slightly warm to cold. If not, the charge is probably low.
Judging by the rapid compressor cycling I'd have to guess that the system is low on charge. As a quick check, feel the low (suction side) hose just before the compressor. With the system running in max a/c and the engine at 1500 rpm or so the hose should be from slightly warm to cold. If not, the charge is probably low.
Logistics Pro
Joined: Mar 2002
Posts: 3,881
Likes: 84
From: Wake Forest, NC
It could also be short cycling if it is overcharged and hitting the Hi pressure cutout, or something is seriously block causing the low side to suck down fast. A guage set showing both sides will tell you so much more. High Ho Silver listed some good indications as to what they will reveal.
