I have been googling and reading the forums. I am a little lost on what to do. I have no A/C in my 1991 coupe. The fan works and it blows air just not cold. I did try the code thing you can do with the A/C unit and it didn't have any codes. I do not see any obvious leaks. The car has never had A/C since I have owned it so not sure what stopped it.
Should I try adding Arcic Air, R12 substation in? Should I just save up and convert it to R-134a? If I do convert it can I just change the O-rings and valves?
Looking for the most budget friendly way to get cold air in the upcoming Texas summer.

 

You have jumped over so many things, first does it have Freon in it is the pressure even close. Does the compressor cycle at all, these cars have a nasty habit of the AC control module getting corrosion and stop working.
So confirm the gas and all connections, and plan on the upgrade or take it to a professional.

 

I do not know what to do. Not trying to jump over things. That is why I am asking for help haha.
How do you test the Freon pressure?
I was told the compressor won't engage with if it has low Freon. So how can I test if it is cycling?

Sorry not an expert with A/Cs and cars. Anything helps

 

If you have limited experience working on cars and especially AC systems, then you need to take it to a professional shop for diagnosis and/or repair. Anyone here trying to guide you would be like instructing a bricklayer how to do heart surgery by text message. Everyone has to learn somewhere but AC systems can be complex (also a tad dangerous if you have no idea what you are doing) and IMO, not the place to start.

 

Buy a gauge set, very available on FB Marketplace or Amazon for around $50+- for a set up worthy for most people. But I will tell you. You are working with compressed gas and you can get a frost burn but if enough gas shoots out as a liquid back off quickly to preserve the charge because it should be enough to run the system.

 

I have experience with cars. Just not so much on A/Cs

 

Alright ill get a gauge set. what is the pressure supposed to be at?

 

Here's a rough guide

 

thank you! If it does need a recharge is it ok to use the R12 substitutions? Or is that bad to mix them?

 

If you are looking for "the most budget friendly way to get cold air in the upcoming Texas summer" then take it to an AC repairman or shop and get it looked at and fixed because you have no knowledge of where to look and how to fix this and will be spending a fair amount of money running around in circles and be on here constantly looking for advice on where to go next. If you want it fixed, then bite the bullet and go to an expert to repair this. It's possible it may be easy (like needing Freon, unlikely if you really have no 09 code)) or it may be well beyond your capabilities (like needing a new compressor).

 

I agree you will be $100 down the road frustrated, heading to a professional. If you where already converted with a weak working system it would be a good learning experience, but this has other problems.

 

Maybe I miss worded my goal. This is my project car. I thought the point of this forum was to come for advice and where to look next? I am attempting to learn something.

When I said budget friendly I more meant. I didn’t want to nuke the whole thing and get all new parts.

if this isn’t the place to ask for friendly troubleshooting advice sorry guys I won’t post. This forum has already helped me get my car from not running to doing 0-60s in 5 second range. So I thought an A/C question would be ok.

 

It's totally ok to ask if you want the Learn,so roll up the sleeves and Get the Factory shop manual( no Chilton's or Hays) and the gauge set make sure you have the pressure. With the manual there's a great Diagnostic flow take notes and test. This substitute gas? I guess it would be ok for testing and probably full Operation but conversion would be best.

 

Thank you! I appreciate the positivity. I will have to wait for the gauges to get in. I just ordered them from ebay. I do have the Factory manual for my 91. I'll start reading! I will let you know what I find with those gauges.

 

Your ahead of the game follow does it do this and does it do that and you should be ok. I had a PITA AC problem that after a lot of head scratching like you (once you confirm it) gas was topped off my compressor would not cycle, turns out was my controller module down on the Firewall next to clutch pedal

 

Reading the manual and getting a set of gauges is the path I myself would take. I really dislike when anyone touches any of my cars, hence my reluctantance to take it to a professional which may not be the smartest thing but it usually works out ok for me. I got lucky a few times and was able to fix several AC units over the years at a relatively low cost. I have no experience with R12 substitutes but haven't read a lot of good things about it. Although illegal you can still get R12 in cans but they have gotten expensive. Try Craigslist. I find you tube to be a hit or miss but when its a hit it can be very helpful.

 

OP, definitely good to follow the diagnostic flow chart in the FSM. It definitely makes it a bit easier!

To answer one of your initial questions about converting to R134, assuming there are no leaks, broken parts, etc, then yes, you just need to change the o-rings and service valves (you'll need R12 to R134 service adapters). I'll add to that though, the A/C oil needs to be changed too. The original R12 system will be running mineral oil, while R134 applications requires PAG oil. All of the old oil needs to be flushed out with A/C flush. My recommendation, and I've seen this mentioned in many other forums too, is to use Ester oil for the conversion. This is what I did on my car too. Mineral oil and PAG do not mix, so after the flush in case there's any mineral oil still left, Ester will be a little more compatible.

To do any of this work though, as previously mentioned by others, you need to be extra careful as the system is under pressure (unless the Freon leaked out). Once you get your gauges in the mail, hook them up to the system to see if there is any pressure. If there is, take the car to a shop so they can recover the Freon. Legally, you can't just openly vent off the pressure to the atmosphere. Once the system is evacuated though, then you'll safely be able to undo each fitting/junction to replace the o-rings and flush the lines out.

 

From my experience on the C4s the clutch on the ac pump has been the weak point. What I would recommend doing is taking off the serpentine belt and try to determine if the pump is good. Also check if there is any pressure in the system. Pull off one of the caps on the ac hoses and see how much pressure it has. A gentle puff, nothing or a strong amount of? Then see how the pump spins spinning the clutch portion of the pulley. If you had a gentle puff of pressure and the pump isn’t frozen you can try evacuating the system with a vacuum pump. You say you have gauges coming. The next thing is a vacuum pump. Once you hook up the gauges you hook the vacuum pump up to the middle port and get all the air out of the system. After 15 minutes of the vacuum pump running you should be able to close the middle port and make sure your system holds the vacuum for 15-30 minutes. If it holds you can simply add r12 if it had never been converted. If your system has remained closed it should have oil and no need to worry about it. From what I’ve seen in California it is still easy to find r12 for just about what a store charges for a can of r134.

 

This ^^^^ statement is interesting. Post up where you can "easily" find a can of R12 for "about what" a can of R134A costs and I will drive down with my one ton and fill 'er up.

 

On FB marketplace people sell the 12 oz cans for about $20. A can of r134 costs close to that. People sell used 30 lb bottles between $20-$300. Right now there’s a 30 lb of r12 in San Diego for $250 advertised as 100% full.