A/C clutch engages and disengages after recharging

[FrostByte]

Hello everyone, and thank you for reading, this is my second post, and I am looking forward to being part of this community. Here goes nothing...

I have a 4.0L 03 Mountaineer, A/C was blowing hot, got a cheap $20 diy recharge kit from the local auto parts store ( i know now this was a bad idea ). So I go about recharging the A/C , before I recharged, the "AC Pro" gauge read around 10 PSI (and the clutch was not engaged) as I was going I heard a snap. The pressure now is in the green zone. However, it drops after the compressor disengages. I put a little more and the pressure is now 35 PSI, at this point the compressor is engaging and disengaging every 2~4 seconds. I go in the truck, NO COLD AIR!

I am a total noob. Is this a compressor issue, a pressure issue, or should I keep recharging it and disregard the needle on the red zone to see if its a misreading ( it happened once in my friends car, he filled it past the red zone and the pressure fell back down to normal. ). I dont want to blow up my truck, or spend hundreds on fixing this, any help is greatly appreciated,

EDIT
Here is a similar psi reader with hose i used for refilling.

 

[FrostByte]

Bump

 

[OneofMany]

Ok- your system has a certain capacity. Look around for any decals under the hood about the A/c system. compare to what you already put into the system. It sounds like you are not at capacity yet. Keep filling the system until you are not dropping below 30 psi while the compressor is engaged. You only have a gauge for the low pressure side, not for the high pressure side, so dont go overboard on filling just in case there is a restriction and your high side pressures exceed tolerance. Wear safety goggles and gloves. The compressor should cycle less often as you fill until it stays on. Rev engine to 2k rpm for a while and watch your pressure gauge to not fall below min tolerance and not cycling the compressor.

 

[FrostByte]

Ok- your system has a certain capacity. Look around for any decals under the hood about the A/c system. compare to what you already put into the system. It sounds like you are not at capacity yet. Keep filling the system until you are not dropping below 30 psi while the compressor is engaged. You only have a gauge for the low pressure side, not for the high pressure side, so dont go overboard on filling just in case there is a restriction and your high side pressures exceed tolerance. Wear safety goggles and gloves. The compressor should cycle less often as you fill until it stays on. Rev engine to 2k rpm for a while and watch your pressure gauge to not fall below min tolerance and not cycling the compressor.

Just tried it again, when the compressor engages, the PSI goes up to 55
when it disengages, it drops to around 20. When I try to recharge it by pressing on the trigger of the hose, the PSI keeps getting higher [obviously] and is about to reach the red zone. The clutch is still engaging and disengaging every 3-5 seconds.

p.s
I am using the 12 oz can of freon i think the capacity is 32oz but the psi reader is scaring me. I dont want the can to blow up in my face.
Time to take it to a pro? or Manifold gauges?

 

[OneofMany]

Just tried it again, when the compressor engages, the PSI goes up to 55
when it disengages, it drops to around 20. When I try to recharge it by pressing on the trigger of the hose, the PSI keeps getting higher [obviously] and is about to reach the red zone. The clutch is still engaging and disengaging every 3-5 seconds.

p.s
I am using the 12 oz can of freon i think the capacity is 32oz but the psi reader is scaring me. I dont want the can to blow up in my face.
Time to take it to a pro? or Manifold gauges?

When charging the system on the low pressure side I would expect the reading to DROP when the compressor engages and to RISE when it disengages. When pressing the charge trigger the gauge will read the pressure in the charging hose and can... What you are telling me sounds the wrong way around unless you are connected to the high pressure side. In which case you must have the a/c disengaged.

 

[FrostByte]

When charging the system on the low pressure side I would expect the reading to DROP when the compressor engages and to RISE when it disengages. When pressing the charge trigger the gauge will read the pressure in the charging hose and can... What you are telling me sounds the wrong way around unless you are connected to the high pressure side. In which case you must have the a/c disengaged.

ill try it again tomorrow morning, you might be right, maybe i'm just saying it wrong but that needle moves a lot when it goes from engaging to disengaging.

i'm using the hose attached to number "2" on the diagram.

EDIT]

forgot to add> when i started recharging the first time [ac was not cool at all] , the clutch wasn't spinning, don't know if that makes a difference, im a total noob, and still don't understand.

also, what would happen if i disregard the red zone and keep filling it? would i make an explosion? or would the ac start working bc it wasnt charged at all? thanks for your help

 

[OneofMany]

With the compressor clutch not engaged there is no danger of that can exploding on you. If you would feel safer, empty the can into the system with the engine off. You will feel the can get cold as it discharges and hear a little noise. The clutch only engages if 1) there is sufficient pressure in the system to close the low pressure switch 2) not enough pressure to open the high pressure switch. This means it will engage and disengage if the pressure in the system is low and re-engages as the pressure between the high and low sides equalize. The contents of that can is not enough to overfill the system unless it was already charged. After emptying that can your gauge reading should drop as the compressor is engaged and not drop low enough to open the low pressure switch. You can press that trigger again until the reading no longer rises as you do. This way you know the pressure in the can and in the system is equalized and the can is fully emptied.

 

[FrostByte]

With the compressor clutch not engaged there is no danger of that can exploding on you. If you would feel safer, empty the can into the system with the engine off. You will feel the can get cold as it discharges and hear a little noise. The clutch only engages if 1) there is sufficient pressure in the system to close the low pressure switch 2) not enough pressure to open the high pressure switch. This means it will engage and disengage if the pressure in the system is low and re-engages as the pressure between the high and low sides equalize. The contents of that can is not enough to overfill the system unless it was already charged. After emptying that can your gauge reading should drop as the compressor is engaged and not drop low enough to open the low pressure switch. You can press that trigger again until the reading no longer rises as you do. This way you know the pressure in the can and in the system is equalized and the can is fully emptied.

You were right
After charging it a little more, when the clutch is engaged the pressure does not drop as much as it used to. It falls to around 25 psi. And rises to less than 55. Ill continue to add more of the same 12oz can and might buy another (capacity is actually 56oz)
Maybe it didn't have any refrigerant and that caused the clutch to engage when I started filling it up. Ill try to add more tonight after work. Thank you!!