Should I add more refrigerant to my AC system?

I will check this out and report back this weekend. And I corrected my thermistor spelling. Thanks!

 

Today was a warmer day 78F. I gave it another shot (i.e. adding refrigerant on the low pressure side). I was able to get the pressure up to 45 PSI which seems about nominal. The temperature at my vents on full/high AC setting was 58deg F. I have some refrigerant left in the can and will give it a go again on a warmer day, like 90F. Anyway, there were not pressure oscillations this time. For now, I am going to declare victory. Thanks @CurtB for the helpful feedback!

 

What was the high pressure?

 

I don't have a gauge on the high side. I have never touched the high side... I realize do this properly I need a better setup. With that said, my theory on what happened in my first post (post #57) is it was too cold outside and the condenser was freezing (and causing the pressure oscillations).

 

Just no. 58f? Not even close. And yer gonna add more when the temp outside gets hotter?!!!!!!!

Watch the vid on post #46. This is the proper way to know how much freon is in the system. By weight.

I'm pretty sure you are overcharged and if you add more... bad things can happen.

So, follow the vid and rent the equipment, or take it to a shop that knows what they are doing.

 

I will watch the video and get a gauge set etc. My "understanding" is that the proper pressure, on the low side, for about 80F (ambient) is up to 50PSI. I started at 14PSI with warm air blowing. Now the AC is working at some level and it pooped out at 45PSI. It is true that I might be missing something but this seems like a pretty standard case of needing a refrigerant recharge. Out of an abundance of caution, I will watch vid #46 and get all the measurements before proceeding. Firstly, I need to buy a kit with the right gauge set.

 

58°F at vents with 78°F ambient means it is not sufficiently cooling and your low side pressure is too high, assuming your gauge is correct. You should test for leaks. A big leak could have caused a lot moisture to get in your system causing freezing and insufficient cooling. Your truck being at an old age like mine, I'm sure something in the AC system must be leaking.

The first time I recharged, I achieved 44°F vent with 80°F ambient and 50°F vent with 100°F ambient. I aimed for 30 psi on the low side using a set of manifold gauges.

Then a few months later it started to lose refrigerant again and I traced the leak to a bad seal and connector at the high pressure hose. I changed the hose and seal then pulled a long vacuum. Since the system was empty I refilled based on using weight. Then temp at the vents were 42°F.

It has been more than the year and it's still holding. Even on a hot 100-105°F day, the temp at the vents would be at 46°F.

 

I would take it to a shop. If you slug liquid into that compressor, instead of a $200 job, its gonna be $1,000+. Trust me. You dont wanna grenade your compressor. I dont wanna be a prick, but you have no idea what your doing.

 

He should be given a chance to try to fix it himself. I did not expect to be able to repair my own A/C but I was able to after doing a lot of research and asking questions.

Some people make it sound like the A/C system is some kind of complicated witchcraft that you need pay thousands of dollars to the dealership to fix.

 

There are many things I learned through this forum that I originally did not know how to do. At the time, I did not know what I was doing: Changing my transmission pan, fluid, front brakes, rear brakes, heated mirrors, engine codes, oxygen sensors, catalytic converters, electrical issues etc. All of these problems and more were solved because of this excellent forum. With a little help, I trust I can solve this problem too. I have the proper gauges on order and think I can get there with some help. Thanks @Hans Moleman !

 

It's a whole lot more than just "freon" levels that would make a AC not cool. Just looking at the low side doesn't tell us much. You COULD be over charged BUT the TXV slammed shut which would give you a low reading. Just one scenario.

I hope OP fixes it and if he's in my area, I have 134a by the drum and all the tools to make the repairs. I do chiller work on a daily basis. And more than willing to teach a crash course on air conditioning principals and why it's really not "cooling" the air......

 

Thanks @UncleRick . I think the obvious first step is to get better gear to really measure what is going on. I have a gauge set coming. I will report back and take it from there. If you are near me I would love the crash course!

 

Definitely. I keep a nice digital manifold at the house, but I have done plenty of work with the Harbor Freight gauge set. Just make sure they are in PSI/F and not PSI/C. So you can see your saturation temp.

I used to teach a 2 hour, thrown down, quick, Car AC class at the college for the HVAC/R guys. It's pretty easy once you understand the components and what your seeing on the gauges (there's more than pressures on there)

 

Here’s some reading info. I found last yr when I replaced my condenser, it may or may not help.


https://www.aa1car.com/air_conditioning.htm