Refrigerant Refill Question

If the refrigerant is missing then you have a leak. Get the leak fixed, then have the system evacuated and refilled. Refilling an empty system with R-134a without first evacuating it is a certain path to trouble.

Thank you for your advice - I guess I will have to leave it for the professionals and avoid a bigger problem...

AC can be costly to repair as I found out when I bought my '96 Camry. Someone had run the compressor after a stone had holed the condensor effectively stuffing the compressor due lack of lubricant and cooling (from the now lost refridgerant). So after $650 for a new Nippondenso compressor,..a drier, and other tests and evacuation then refill,..I was up for the best part of a thousand smackers,..but, ever since then, in our

Jason

Many air conditioners may leak a small amount of coolant with time. If you are still cooling after 5 years, clearly you have not lost ALL your refrigerant. You may have a small leak that is really not worth the expense of fixing it.

The 134A kits (with good quality hose and pressure gauge) are easy to use, and you can top up your refrigerant charge easily. Read the instructions, go slowly, and charge conservatively.

If you have a major leak, then a professional - not necessarily a dealership - is the way to go, but for a small top up, those kits work fine.

I did not use the A/C for a long time, last summer I hardly drove the car, and so far it had been nice weather. The A/C is working, I think it got better when I tried it for the second time, but maybe it just because it was not as hot outside. As I started the A/C I saw some bubbling through the check glass, which gradually reduced their activity, but it never ceased. I read the procedure in Chilton, and some theory about car A/C operation, and therefore I believe that some refrigerant is missing but there is no major leak. I think I should try to do it myself, and invest the money I would save into a more professional equipment (and proper gloves and eye protection for any accidents with high pressure refrigerant...).

Thank you for your advice.

You are lucky to have a sight glass. It can be helpful for topping up the charge.

When you turn on the AC, it is normal for the refrigerant to have bubbles at first, but it should clear up after a short time. Since yours doesn't, it is an indication that you are a bit low on charge.

Buy the kit with a can of R134A, hose, can tap, and pressure gauge. Follow the instructions on how to set it up. You only add refrigerant into the low pressure side of the system, and usually this is simplified by the fact that your kit connector won't fit on the high pressure side.

The car should be running, the AC on full, and the doors open. Keep the refrigerant can vertical, so that you will only add vapor to the system. Watch the pressure gauge (and the sight glass). When your bubbles disappear in the sight glass, you are nearing optimum charge. The pressure gauge will give you a more reliable measurement.

You open the valve on the can tap, allow some refrigerant to enter the system, and you will see a corresponding change in pressure on the gauge. Stay within the guideline limits of pressure. After each addition, let the pressure reach equilibrium... this can take a few seconds. Don't overcharge.

This is a simple and safe process. Always, when you are working under the hood of a car with the engine running, be sure not to get tangled up in the fans or belts, don't let metal parts ( a wedding ring is a particularly bad one) get across electrical cables, etc.

Thank you for the detailed instructions. When I first connected the pressure gauge, it showed about 15PSI. After I open the valve on the can tap it went up to 25 and stayed there. I tried to to keep valve fully open and and rev up the engine, but it did not make a difference. The pressure stayed on 25 PSI when I closed the tap, but there were still bubbles in the sight glass. I'm planning to repeat the procedure next weekend, and thinking of how to improve the results. I read that it is advised to put the can in warm water (105f/40c) to increase the pressure in the can. I avoided using this method because it was not mentioned in the instructions and I assumed that the can is already pressured enough. Another possible cause is the fact that it was pretty cold outside while I was charging the system in the morning. I hope that next weekend I would be able to do it in the afternoon.

I will update again with the results. Thanks again for your advice.

Update - today I had a chance to test the A/C at 2pm after the car stood in the sun all day, and within few minutes the car turned into a meat locker. So I am pretty happy with the $27 solution, not to mention that the can is still almost full and can be used for future refills.

The only question remaining - I can still see activity in the sight class. I do not know if it is different the low refrigerant - before it looked like bubbles coming up and now it looks more like a flow of water. Maybe it is related to the fact that in my first attempt I was only able to bring up the pressure into 25PSI, which is marginal. I am still planing to try increas the pressure, just in order to see whether it would clear the sight glass activity.

Sometimes you run into a situation like that where the system doesn't seem to want to take the charge at first.

Sometimes you haven't punctured the can very well. You can run the puncture needle back into the can deeply, and retract it again, to see if this frees up the movement of the refrigerant. (Note...that refrigerant you had left over wont last too long.. It WILL usually leak out, no matter what you do)

Sometimes the charge valve and hose adaptor seem to resist flow of refrigerant. You can jiggle a little, remove the hose adaptor and then reinstall it, etc.

And definitely yes, you can set the can into a pan of warm water. Maintain the can in the vertical position. You can even shake the can a little but keep it vertical. Be patient.

Don't try to charge liquid refrigerant into the low pressure side of a running compressor. Some people do it and get away with it, but dont risk it.

Be sure you understand what I am saying here. Keyword is LIQUID. I am not saying to charge refrigerant into the high pressure side of a running compressor under any circumstances.

Sorry it took me long time to update - Last weekend I had to work and had no chance to try charging the system until today. I tried the warm water technique today, and it got me up to 28 PSI. The water were not hot, just a little warm, so it is possible that I could get more with hotter water. I think I am going to going to leave it this way right now and don't risk it by introducing to much liquid into the system. It was very hot outside when I did it, and when I got back into the car at the end of the procedure, it was very cold inside. I don't think that there is a major leak because there was no pressure drop in the last 2 weeks. I guess that recharging the refrigerant can be considered as normal maintanance, this is the way I see it now.

Thank you for encouraging me to charge the system, it worked well and saved me time and money, and I am also happy that I learned something new. Thanks !

Use the fluid the manual states.