Did I break my AC?

Tigerman

Tigerman

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Hello,

I think I might have screwed up my AC, but you guys are the experts, so here is the story.

The AC on my 1998 was working fine except not too cold. I decided to do add refrigerant, you know, the A/C Pro can...
Well, I followed the directions, set the temperature on the gauge, ran the ac, noted the pressure and filled it up. At first the pressure seemed to be borderline but slowly fell as I added the refrigerant (shouldn't it rise? Or was my compressor still off when I started?). I stopped when the can was 2/3 empty. It kind of felt awekward, I did not feel right about it. Anyway, the AC right after seemed to work better.

Two days later, as in right now, I turned on the AC and this nasty, grinding+hissing noise came from under the hood and I felt a significsnt power drop. A few seconds later the noise repeated but lower in pitch and shorter in duration... once again this repeated and finally went away completely, but I turned it off anyway.

What do you guys think? Did I put too much? How to properly check?

Thanks
 
Sounds like your clutch may be slipping. You need to install a set of gauges on it and post what the high and low pressures are while operating.
 
Daryl said:
Sounds like your clutch may be slipping. You need to install a set of gauges on it and post what the high and low pressures are while operating.
Click to expand...
Thank you Daryl,

Will this work?
https://www.harborfreight.com/ac-r134a-manifold-gauge-set-60806.html

In the meantime here is what the A/C Pro gauge is showing now on the low side after running the AC for a few minutes.
20180911_141413.jpg


Is this just condensation or coolant leaked as a result of overfilling?

20180911_141419.jpg
 
Unfortunately it sounds like the compressor is locking up. This will cause a clutch to slip also. It’s possoble it’s just overcharged but it’s also possible that when you brought it up to proper charge the extra work the compressor was doing took over to the dark side.
 
Just called Autozone, they have a set I can borrow, will be heading there in a bit.

Any advice on correct checking procedure? I mean besides basic knowledge that compressor raises the presure (low side before) and (high side) after being compressed I have no other knowledge of AC.
 
Tigerman said:
Just called Autozone, they have a set I can borrow, will be heading there in a bit.

Any advice on correct checking procedure? I mean besides basic knowledge that compressor raises the presure (low side before) and (high side) after being compressed I have no other knowledge of AC.
Click to expand...

Make sure both the valves on the manifold remain closed. When you attach the quick release service valves make sure they are turned all the way out (counterclockwise) before attaching them. Once attached turn them clockwise to depress the schrader valves so the gauges will read pressure. Start the Jeep and turn the A/C on high. Read the pressures.
 
Ambient temperature is 84F. These are the results after running the AC for 5 minutes:
20180911_151550.jpg


Low pressure: 42 PSI
High pressure: 235 PSI

According to your posted numbers the high pressure is good, the low pressure in 1 PSI higher than maximum, should I let a little out?
 
Tigerman said:
Ambient temperature is 84F. These are the results after running the AC for 5 minutes:
View attachment 55054

Low pressure: 42 PSI
High pressure: 235 PSI

According to your posted numbers the high pressure is good, the low pressure in 1 PSI higher than maximum, should I let a little out?
Click to expand...

No, don’t let any out. What is the air discharge temperature at your vent closest to the evaporator. Also, is the noise you were hearing earlier still there?
 
The pressure looks pretty good. You might be slightly overcharged since the ambient is pretty cool but not enough to cause your problems. Rev the engine to about 2000 and watch the pressure. The low side should drop to about 22 and the high will probably be about 260. Watch the needles. They should hold pretty steady. A jumpy needle means bad compressor. You might have to watch it for a while until you see the problem if it’s a clutch.
 
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These systems are really picky about proper charge. The capacity is 20 oz. that is less than 2 cans. Sometimes a full evac and recharge is all you need. Even a few extra oz of refrigerant will cause poor performance.
 
Daryl said:
No, don’t let any out. What is the air discharge temperature at your vent closest to the evaporator. Also, is the noise you were hearing earlier still there?
Click to expand...

The noise is not there, it seems to be working very well at the moment. Shocks, I do not have a thermometer! Let me see If I can find one, lol.
 
Tigerman said:
The noise is not there, it seems to be working very well at the moment. Shocks, I do not have a thermometer! Let me see If I can find one, lol.
Click to expand...

You may have just introduced a little liquid into the compressor when you were charging it. Do what Nimbley suggested and if the pressures still look okay and it’s blowing cool air, run it.
 
Daryl said:
You may have just introduced a little liquid into the compressor when you were charging it. Do what Nimbley suggested and if the pressures still look okay and it’s blowing cool air, run it.
Click to expand...
Good call. I didn’t even think about liquid because I’ve always used a guage set. The DIY charge setup doesn’t have a long enough hose so liquid could definitely have been the problem.
 
Nimbley said:
The pressure looks pretty good. You might be slightly overcharged since the ambient is pretty cool but not enough to cause your problems. Rev the engine to about 2000 and watch the pressure. The low side should drop to about 22 and the high will probably be about 260. Watch the needles. They should hold pretty steady. A jumpy needle means bad compressor. You might have to watch it for a while until you see the problem if it’s a clutch.
Click to expand...

The low side at engine start and a minute into it was about 45, stayed at 45 though higher RPM. The high side was 240, but went up to 300.
 
The A/C is blowing as cold as Jeep AC can, I think (I have a RAM truck and it does about the same). Cound't find a thermometer to measure the temp at evaporator.
 
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