Hi. Brand new to the forums and this is probably the wrong place to post this but I looking for information on the AC unit on a 1991 Buick wagon. Can I recharge myself or do I need to take it to a shop. I am good with tools but brand new with car stuff. But I figure 62 is a good age to learn. Thank you
You can do A/C repair yourself, but it does require some specialty tools and some basic knowledge of how the system works. Is your Buick still R-12 or has it been converted to R-134a? Either way if it needs a recharge then that means it has a leak which needs to be addressed first. You will need a gauge and manifold set to start. You can get the cheapy Chinese set from Harbor Freight. I bought a Yellow Jacket manifold gauge and hose set for a little bit more, but the quality is very good. Another specialty tool that is nice to have is a good vacuum pump. I lucked out that my grandfather was a Chrysler mechanic for 40 years so I inherited an ancient Robinair vacuum pump (another nod to buying quality tools that will last). The manifold and gauge set are used to monitor system operating pressures. You can't really see what is going on without them. The vacuum pump is used to pull a vacuum on the system to pull out any water from the system and check for leaks. You can have a shop do that, but it sure is nice to be able to do it in your garage rather than have to take it to a shop. Does the compressor kick on at all? Probably where I would start is adding some refrigerant with a UV dye (make sure it does NOT contain a sealer of any sort). You can get a $10 black light flashlight from Home Depot which will highlight the UV dye and hopefully allow you to find leaks. Once you find the leaks you can have the system evacuated of refrigerant (have a shop do this). Hook up the vacuum pump and let it pull at least 29" of vacuum for about 30 minutes (longer if you can). Close the system and turn the vacuum pump off and make sure the system can hold the vacuum (the longer you can monitor it the better, but I usually shoot for at least 30 minutes). If it holds the vacuum then it should be leak free. At that point you can add the required amount of refrigerant. Obviously I am glossing over a lot of steps, but that is a basic rundown. It's not hard to do, but it does take patience, time, knowledge, and as mentioned some special tools. I'm far from an expert. I'm just a self taught DIYer.
Thank you very much for the information. This sounds like it might be a shop project. It would be nice to find a shop that would let me watch them, ask questions, and get a feel for whats going on before I tackle something like that. I was hoping it was a simple "grab a can of stuff" and put it in there. Again thank you.
Well there is that method too. Has your system been converted to R-134a? You can try your luck and go to the parts store and get one of those cheap recharge kits (if it has been converted). Unfortunately it's hard to tell how much refrigerant is in your system so I have no idea how much you'd need to add. I also can't say how long the charge will hold. It might hold for a week or it might hold for a year. Whatever you end up doing do not put anything with a sealer in it or any other product offering to seal any leaks in the system. Those are bad news. I know 50 people will chime in about how they worked great for them, but in my opinion the only proper way to fix the leak is to open the system up.
The first step I would do is have someone check the system (a lot of places will check it for free, hoping to get a big payday). You can then tell them that you have to think about the repairs they suggest (cost is a good reason). You can then decide if it is worth the money, or if you want to do it yourself. They will tell you if it is converted to 134a or not. If it is currently working and the compressor is cycling on and off rapidly, it needs refrigerant. If the compressor is not running, you can bypass the pressure switch and determine if the compressor runs. If the compressor runs with the bypass, you may just be very low on refrigerant. Make sure you have the right refrigerant. If it is converted, only the 134a connectors will fit the lines. If it has not been converted the 134a connectors will not fit (one should have a blue cap for the low side, and one should have a red cap for the high side). Refrigerant is added on the low side (blue cap).
