AC Manifold Gages Issue

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Quick question regarding ac gages. I've used my set quite a few times over the years (have to recharge about once a year) with no issues. Today I went to recharge my ac and had a weird issue with my low side gage. Ambient temp was 100, low side read 40 and as I added r134a, the high side went up as expected but the low side wouldn't move.

My temperature pressure chart shows low should be 50-55 and high should be 315-325 at 100 degrees. Well, high side reached 325 no problem but the low side never moved off the initial 40psi.

If I kept filling to about 350 on the high side the low side would suddenly spike up to about 65 psi.

I'm thinking my gages have taken a dump on me, anyone have any thoughts about what is going on here before I buy new gages?
 

Daw14

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Could be a hose went internally bad, one of the layers let loose.
 

crazykid1994

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It may be a good idea to figure out where it’s leaking from and fit that as that could be part of the problem or possibly your gauge going bad. Check with another gauge to confirm
 
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I have a new set of gages coming today. I will try those and report back. Also last night when I took the coupler off the low side service port the Schrader valve was leaking, I could hear gas escaping. Hopefully that's where my leak is.
 

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Did you check the suction line temperature? There maybe a problem with the expansion valve or a plugged/dirty evaporator.
 
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I don't have an IR gun but it's cold to the touch. My new gages just arrived so I'm going to go out and see if I can figure out what is going on
 
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New gages show LS was low at 30psi. Added r134a and high side reached the right psi but low side stopped at 40 (supposed to be 45-50).

Pretty much the same issue as the other gauges, won't go past 40 on LS.
Not sure what is going on, LS is 5-10PSI low and HS is normal.

Vent Temps are only going to 60 degrees (96 outside when measured).

Perhaps I introduced air into the system which is why it's not cooling well despite pressures being normal on high side a little low on the low side?

I may just take it in the have it vacuumed and refilled and see what happens. At least then I'll know there's no air in the system.
 

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crash68

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air in the system would cause everything to go high, some more than others. Get a contact thermometer probe, take some good readings of the suction line and the temperature drop across the evap.
Having the charge weighed in is a good idea.
 
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Bear with me, as you can tell I'm no ac expert. I can measure the temperature of the suction line no problem, but my understanding is that the evaporator coil is in the hvac box under the dash.

Probably a very dumb question but how do I get access to that to measure the difference in intake air and output air (the temperature drop)? I assume the output temp is the same as the vent temp since that's where the cooled air ends up?

This week I replaced my trucks thermostat and fan clutch. Getting annoyed with her shenanigans haha.
 

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Probably a very dumb question but how do I get access to that to measure the difference in intake air and output air (the temperature drop)? I assume the output temp is the same as the vent temp since that's where the cooled air ends up?
Only would have been dumb not to ask.
For the inlet air temperature, stick the probe in at the air filter opening or just above that through the recirc door opening. The temp coming out of the vents is fine. Check the suction temp as close to where it comes out of the firewall and the system should be set in Max Cool (recirculation and fastest fan setting).
 
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