I live in HOT Arizona and my high side gets up to the 320 to 350 Psi mark the low side is around the 45 Psi side during the peak summer heat that's around 115.

You can get a special orifice tube for 105 and higher air temps I may try one out in the future.

 

My suggestion in this order

1. Dump all the Freon

2. Change out your A/C Receiver Drier / Accumulator and A/C Orifice Tube use new seals and replace your shradder valves if you can a good idea as they tend to leak after 8 years of abuse from heat and cold in the engine compartment.

3. Pull the required vacuum on the system check for leaks

4. If no leaks and the system holds at the required vacuum go to #5

5. Inject one 3oz. can of PAG 100 oil with ICE as you will be low on oil after replacing the A/C Receiver Drier / Accumulator

6. Use a gauge set to fill the system with Freon/R-134a use a thermometer in the main air duct till you see the desired temp and Low and High Psi readings remember the Psi readings are more a guide than Law.


Pictures below for a (2000 Dakota)


A/C Receiver Drier / Accumulator



Orifice Tube


Oil



A/C System Valve Core and Cap Kit



A/C System O-Rings, Seals, & Gasket Kit

 

lots of updates since my last post.

1. i borrowed some equipment and recorded some data while driving (don't ask). on a ~75° day, my high side pressures were between ~130-200 psi when it was cycling. the low side was ~25-50psi while cycling. it turned off for no reason, and only once did it turn back on on it's own (without me turning the switch to the off position for awhile first)
2. i put in some dye and checked for leaks with the black light. no leaks that i can see.
3. i jumped both the high and low pressure switches while the clutch was not cycling, no fix.
4. just for grins, i replaced both switches. no fix.
5. verified that the electric fan turns on with the selector switch, so i believe the HVAC control unit is fine
6. this is where it gets interesting. i pulled the AC compressor clutch off. i've heard sometimes they have 2 washers/spacers between the clutch and the pulley, and as the compressor magnet and clutch age, it becomes a weaker magnetic pull and can't overcome the distance between the pulley and clutch as well as it could when it was new. apparently you can remove one of the spacers and it will work again. mine only had one spacer...so maybe the other was removed at some point in time before i owned the truck. but looking at the back side of the clutch, i think i'm getting close to at least one source of the problem. (see attached picture). clearly this has not been engaging evenly. anyways, i removed the only spacer and put it back together. it cycles on and off with the switch (i was worried it would stay engaged when it wasn't supposed to because it is that much closer to the magnet now). i cycled it ~30 times on and off, removed the clutch, and re-inspected it. it looks as if the rusty part seems to be breaking off, like that portion of the clutch is now contacting the pulley, which is a good thing. on top of that, the first time it cycled, it seemed to "slip" before it engaged. by the time i cycled it 15 times or so, it caught pretty much instantly. so, regardless of whether or not this is my issue, or if it will solve the problem, i think it's a step in the right direction.

thoughts?

 

A bad clutch can cause your a/c problems.

In regards to the shims, this is from the FSM on setting the air gap:

Check the clutch air gap with a feeler gauge. If the air gap does not meet the specification, add or subtract shims as required. The air gap specification is 0.41 to 0.79 millimeter (0.016 to 0.031 inch). If the air gap is not consistent around the circumference of the clutch, lightly pry up at the minimum variations. Lightly tap down at the points of maximum variation.

 

Wow that's very bad

If I remember that was one of the things I said look at

Now replacing that may not fix everything but it looks like its not engaging properly as only one small portion of the clutch is making contact with the pulley.

Replacement clutch's are hard to find but not imposable most replace the compressor.


Just be careful as you can get the wrong part sent to you

I replaced my clutch you just need a gear puller your clutch plate is way more worn than mine was and I had problems with slipping

 

Some Pic's that may help

I forgot you need some snap ring pliers also

LINK to my pic's

 

I forgot to mention one thing as the clutch snaps on/in it should have a loud snap or click if not the magnet is weak the magnet may give out as you drive also if bad.

So your problem could be two fold bad magnet and worn out clutch plate.

But the clutch kit includes both the pic shows what you get a new pulley, clutch plate and new magnet.

BUT almost everyone will tell you to just replace the compressor as 99% of the time that's what a shop would do.

Why your compressor could be bad or going bad if old so the best choice is a new compressor.


I knew my compressor was still good that's why I replaced my clutch----only

 

where did you get your clutch pack? it looks like you replaced the clutch, pulley, and magnet all at once? i'm hoping to get just a clutch...or see how removing the shim will work. i'm thinking if it doesn't work, i might just try to find one at a junk yard or something. it can't be hard to find a used one in better condition than mine! :-)

 

A clutch kit is all 3 parts pulley, clutch plate and a new magnet you must replace all three as usually the magnet is part of the problem you cant just swap out the clutch plate.

Its a kit all three parts if you look at the pulley its worn down also as that's the other mating surface both sides become worn down.

If all you did was replace the front plate you are wasting your time.

 

As a temp cheap fix you could get away with just replacing the plate with a used one.

But its a 50/50 your fix will last one or two years at best or not work at all if the magnet is part of the problem