So my A/C wasn't blowing cold. I got one of those recharging valves and some R134a refrigerant and put in a small can. Afterwards it was blowing nice and cool. (That was last summer)
Fast forward to today it's getting hot again but my A/C blows warm air. I hooked up valve and pressure is there. However A/C pump is cycling on and off every few seconds. Is it just low and I have to put in more? When it's cycling gauge goes all the way to normal pressure and then back down to 0 and then it repeats it as A/C pump is cycling on and off.

 

Low and needs more.

You have a minor leak somewhere.

 

added another can of R134a, blows cold air now but still clicking.

 

Might be just a bit low, but if it is cold I would leave it without a proper set of gauges.

 

the way the system works is the compressor sucks the 134 and pressurizes it into the condenser side. If there isn't enough 134 in there it runs out of 134 on the low side to suck, and you have 0 psi there. There is a switch in the system that cuts off the compressor when the pressure gets too low on the low side.
You need to add more to keep the compressor from cycling too often. I suggest you add a can of dye so that the next time it gets low you can look for the leak.

Chris

 

So I've put a manifold on there.
When truck is not running
low pressure reads ~74 psi
high pressure reads ~75psi
When truck is running
low pressure goes up to ~47 psi and drops down (a/c switches)
high pressure goes up to ~100 psi and drops down a bit.
Is there a congestion in system somewhere or my system is overcharged/undercharged?

 

the high low reading change with out side air temp. and depending on temp, low side should be 30-45 psi high side 150 -250 ,relavent to out side temp thats with the comp running

 

When AC is off. The pressures will try to even out. Running properly, you will see low side around 30 high around 150. That is a rough estimate. Other variables may change that. If it cycles a lot it's either under or over charged.

 

I've uploaded video of it, please help me diagnose the problem.
http://www.youtube.com/watch?v=Oku6_...ature=youtu.be

 

Still way low, at least 1 perhaps 2 more 12 oz. cans. When the compressor cuts out that fast, it is a gimme.

 

Should I be worried about low pressure side being too high?

 

You have to get it stabilized before you can worry about it being too high. In other words, the pressures you are shooting for are with the compressor engaged, as soon as it kicks off, the system will start to equalize, raising the low side pressure.

Shoot it with another can and you will see what I am talking about.

 

I went through the same thing. My pressure was too low, and it cycled quite a bit. I ended up going to a real shop, found out it had almost no freon, fixed the leak and added freon in. No big deal. I freaked out when my autozone freon tap and gauge said the pressure was in the danger zone, but I too just needed it to level out.

Fill it, add dye, and see if you can tell where it leaks out. The heat exchanger in the dash went on mine, and I was able to see the little fluorescent bits on the passenger side dash duct work. My second major leak was the back of the compressor where the hoses bolt on.

Best of luck.

 

I did that, now I have nice cold air. I'll see if there's leak once it gets dark outside (my truck wont fit in the garage )