I've also thought about buying the tools, but then decided against it. I've owned my E46 for 10 years and I have had to top off the freon twice. There's evidently a small leak but so small that it can't be found very easily. I just didn't think it was worth the investment since I would only use it every few years. A better investment for me was to put the money towards parts. YMMV

 

Yeah, that's where I was six weeks ago. I paid the shop $150 to evacuate the system before I did the work, and to vacuum test and recharge. I liked the idea of someone with the right equipment and experience looking it over and recharging. However, I'm concerned that I missed a leak, or anything goes wrong that I need to recharge again in the future, I'd be spending a ton of money.

I'd love to hear from anyone who has bought the tools and did it themselves. Was it worth it?

 

Schrader valves on the service ports leak with age. Cheap and easy to replace the cores on both and suggest doing before a evac and recharge. I bought complete AC o-ring set and then changed all. Nice and cold with no issues for 4-5 years. ⛄ GL

 

Yep, I did the schrader valves too during the rebuild. I reused hoses and evaporator, but I thoroughly cleaned and flushed those. I’m quite certain this o ring caused my leak this time. There is dye in the system so it was easy to trace. I’m not sure how the o ring got damaged, but this time I used a lot of oil, seated it, then took it out to make sure it wasn’t getting damaged on install.

I’m leaning toward buying the tools. I feel like if I run into any other issue again I’ll be wishing I did it myself. Plus, I have 30oz of R134a sitting in my garage.

 

I bought manifold gauges and then "rented" vacuum pump from auto parts store. If you can rent both, all the better. Been a while but, as a leak check, I drew vacuum for 15-20 minutes, stopped, read gauge, then waited 4-5 hours and rechecked that it was holding. Drew vacuum for hour+(?), charged with freon and added dye. Used electronic scale e.g. jewelry to measure final portion from can. Not hard but does take patience and attention. Don't remember how I did PAG oil. GL

 

No need to replace the dryer so soon. A newish dryer will be fine with a over 30 minute vacuum applied to the system.

The drier is not desiccant, contrary to popular belief.

 

Gotcha. That's good to know. I did buy a new drier and a pressure switch, but maybe I'll hang onto those or return. The AC system was really only open yesterday for an hour while I replaced that one o ring, and inspected the others. When I took the hoses off, there was a bit of pressure in the system (I'm guessing less than 1 PSI) so it wasn't exposed to the atmosphere for long.

 

Although it's been since I've cut open a rec/drier bottle..... It's a large porous stone. Tantamount to those little aerator stones one drops into a starter fish tank with the air hose hooked up to it.
It operation is to provide a large surface (big stone with many holes in it) for the refrigerant to pass through. It temporarily captures any moisture (biggest common enemy of A/C systems) and drops it to the bottom of the cylindrical tube.
Hence why at least a half hour of vacuum (I shoot for 45 minutes) to evacuate any moisture.

Now this doesn't mean 20 year old ones are good. They're not, because the stone gets clogged with debris.

 

Only other part that's a sometimes fail is the expansion valve. In your case, likely judgement call; may want to search forum for more background. I replaced it, and leaking condenser, during my ac overhaul. If you have the hvac blower out, cleaning the evaporator (i.e. evaporator cleaner) may be prudent. Evaporator leaks are fairly rare in my perception; certainly more rare than their diagnosis. Sounds like you're on you way. GL

 

I did change the expansion valve during the rebuild, and the system was working great until the refrigerant leaked out, so I think I'm good there. I also flushed the evaporator and hoses with the canister that attaches to an air compressor hose. Doing the hoses wasn't bad, but the evaporator was a disaster. I had a rubber hose connected to help drain the evaporator, but with the air pressure, it blew off and I sprayed the flush cleaner and pag oil everywhere. Good times.

 

Random question, to what pressure should it be fulled / pumped?

 

My understanding from reading up and watching half a dozen YouTube videos is to pull to about 29 in Hg of vacuum. Vacuum for 5 minutes. Let it sit for 10-15 minutes to see if it holds. If it doesn't, you know there's a leak. If it holds, you probably don't have a leak, but until you pressurize, you won't know for sure. Mine held vacuum for an hour last time. Once you think you don't have a leak, you pull vacuum for 30-60 minutes to remove any air and moisture from the system.

My gauges and pump arrived early. I'm still waiting on parts though. And the self-sealing R134a can tap I bought seems faulty. I can't screw it on the can without refrigerant escaping regardless of which way the knob is turned. I'll try another from Autozone tomorrow. Parts should be here Thursday. I plan to do the work early Friday. I'm in AZ. It's bloody hot out all the time in summer, but slightly less so in the morning.

 

Update! I've got working AC again.

I installed the new drier, and a new refrigerant pressure switch. Maybe that was unnecessary, but I felt like I'd rather have a fresh drier, and not a 19-year-old switch after getting to this point.

This is the AC tool kit I bought including gauges and vacuum pump: Amazon.com: Kozyvacu AUTO AC Repair Complete Tool Kit with 1-Stage 3.5 CFM Vacuum Pump, Manifold Gauge Set, Hoses and its Acccessories … (KZTA35011): Automotive

I don't have anything to compare it to, but the gauges seemed to work like they are supposed to. It was in the 90 degree range in my garage. With 26 oz of refrigerant, I ended up around 45 PSI on the low side and around 230 PSI on the high. To be honest, I was really focused on watching refrigerant flow and weighing the can toward the end, so my memory might be off.

The vacuum pump worked just fine. To start, it pulled vacuum down to 29-30" within a couple minutes. It was quieter than I expected , compared to the videos I had watched. After the first pull to full vacuum, I closed the high and low side knobs to let it sit for 10-15 minutes to check for leaks. It turned out I had to run into work for a meeting that went really long, so it sat for over 2 hours and didn't seem to drop at all. I turned the pump back on and let it run for an hour to get any remaining air or moisture out. After closing the low and high knobs, I removed the vacuum pump. I suppose I could have saved myself some money if I had done the Autozone loaner pump, but I don't regret my decision. Running back and forth to AZ, making sure it's available, and maybe having to do that again in the future were potential hassles I'm glad I avoided.

When I got to the recharging stage, I went really slow to make sure I was following all instructions, checking for leaks, purging lines, etc.

My biggest struggle doing this project was the can tap. I already had 2 self-sealing cans sitting on my shelf, but no tap. The tap that came with the above kit was the older puncture type. I bought a new tap on Amazon made for the self-sealing cans, but I could not screw it on a can without refrigerant leaking before it would seal. I went to Autozone and bought another tap made for self-sealing cans, and it went on just fine. However, the outlet was a larger flare fitting than my hose, so I couldn't use it either. My third attempt was the little blue plastic adapter that screws on the self-sealing can and allows you to use the puncture type tap. This wasn't perfect, as there was a bit of a leak screwing the tap to the adapter, but it was 1-2 seconds, and only with one of the cans.

My second biggest struggle was self inflicted. I opened up the first can to start charging the system with the car off. One of 50's Kid's videos did it this way rather than starting the car first, and it seemed a wise way to go in case there were any major leaks, I'd be able to hear them without the car running. That went fine and the system took some refrigerant and then equalized so it wasn't pulling any more in. I started the car and waited for the compressor to kick on, but it didn't. After a minute of panic wondering what I screwed up and if I'd have to tear everything apart and start over, I took a breath and wondered if I had reinserted the wire connector for the AC clutch. I had not. I reconnected it and started the car, and the AC compressor immediately kicked on.

The first can went in just fine with the compressor finally running. An 18 oz can, which was 17 oz of refrigerant and 1 oz of oil. Before this repair, it looked like I had leaked about an oz of oil with the bad o ring leak, so went with it. The second can was 12 oz of refrigerant, so I put that on a scale before opening the tap, and kept remeasuring until it was 9 oz lighter.

I took the car for a short drive in the 100 degree plus weather in July in sunny Phoenix, Arizona, and everything seems to be working great again.

It's not a super difficult job, but I'll say it was nerve racking at times following the steps and making sure I did them in the right order. I was also a little afraid I'd screw something up and have a can or hose explode. I'm guessing if you follow the instructions, there's a very low probability of that, so it most likely was just anxiety doing something new that I don't deeply understand.

Overall, I'm glad I decided to purchase the gauges and vacuum pump, and do the work myself. I learned something new, and now I feel way more confident that if I have a problem again with the AC in this car or any other, I can tackle it myself with enough time and patience.

 

Glad you got it done.
My only advice is one should avoid introducing liquid into the low side if the car is running.

 

My only advice is one should avoid introducing liquid into the low side if the car is running.

This means don't turn the bottle upside down as compressor would be damaged if it tries to compress liquid.

 

With the car not running, I just opened the refrigerant and let the pressure equalize without moving the can around much. Definitely not turned upside down. It seems like this method's biggest advantage is being able to hear system leaks much better with the car off. But I understand what you guys are saying about the risk to dumping liquid into the compressor.

 

Nice! You probably won't know with certainty till next summer, but I bet you got it. Congratulations and enjoy your cool car.

 

Thank you much! 28 hours, so far so good!! Haha

 

Happiness is a cold car. Congrats!

 

3.5 weeks later and all is working well. Which is pretty great, because it was 111 in Phoenix today.