Automotive Air Conditioning Information Forum

Last year I wanted to give air small boost, I bought can of 134a and low side port hose and gauge.( have real set of gauges now).So I watched the AC Pro video on youtube, easy enough except it is showing you what to do when it needs a full charge. "Hold trigger down for count of 5" etc... Ha Ha Anyway I over charged it and compressor was kicking on and off. I had to leave hose on low side port,take can off and use trigger to vent in a jar with duct tape seal to try keep much as possible from venting out into the air. In process I lost a lot of yellowish looking oily substance. I'm going to assume that was my 150 pag oil. Is this correct? I also let to much r134a out ( I know now screwed up but I have learned greatly since then. I had just never had messed with air compressors.. So I got new can of r134a without any additives and filled to proper amount according to temp outside and levels it should be at which was between 32psi and 45psi on gauge.Anything over 55psi is in the red. I went with 35. Air is cold but seems to put more of a drag on the motor than it used to before I screwed it up (Hard lesson learned). Mechanic shop near me says if compressor is pretty low on pag oil then when it gets hot there is more friction on components in compressor, which will put more of a drag on engine and wear compressor out sooner. Now my question, I have 2007 impala lt with 3.5L flex fuel motor. No leaks that I can see on compressor. It calls for 150 pag oil. Everywhere around here only carries 100 pag oil in 3 oz can mixed with r134a 1 oz, 1 oz pag oil, 1 ox of ice 32. performance enhancer. Says to hold can upside down for 1 min after it is done to get all the oil from can. Will this help me with extra drain on engine? And could the ICE.32 enhancer hurt anything inside the compressor. Itg is 100 pag oil medium viscosity, I don't believe that will hurt anything mixing with rest of pag 150, Is this correct? So that's 3 questions. Thanks if you took all the time reading this long post and double thanks if you respond!!

I'll offer some thoughts.

As I mentioned in another thread, I normally don't recommend topping-off or boosting the refrigerant charge because you never really know exactly how much you have in the system to begin with, and you can't determine the correct charge from pressures, particularly just the low pressure. As you discovered, it's easy to undercharge or overcharge it. Best to start from a well-held vacuum and charge to the exact weight as specified on the engine-compartment decal.

Speaking of pressures, you haven't provided any low and high pressures yet as measured with your proper manifold gauge set...windows down, blower on high, and engine running at about 1,800 RPM. Those pressure readings will help us diagnose what's going on.

I hope that whatever you put in the first time didn't contain any sealer, which can cause even more problems than you had before. ICE32 is reported to be a lubricant enhancer. I've never used it, but I haven't heard any horror stories from its use, either. From what I can tell, it's rather benign. But why tempt fate? I'd just stay with pure refrigerant, plain PAG oil, and if necessary, a little UV dye for leak checking just as GM did at the factory.

The liquid that you collected in the jar wasn't refrigerant. That would have just vaporized almost as soon as it came out. As you suspected, it was PAG oil mixed with UV dye. I don't think a little PAG 100 mixed with the PAG 150 already in it will harm anything. The 100 is a little lighter viscosity than the 150. The more important issue is to know you have enough oil in the system, but not too much. Hopefully, you measured what came out in the jar so that you can put back the same amount. There is no dipstick to gauge how much oil is in there, although I'd guess a system like yours came from the factory with about eight ounces total in it.

Those cans with the trigger and gauge are notoriously inaccurate, so it's just guesswork at this point how much refrigerant you have in it now. Maybe you guessed right, but maybe you didn't. A charge that's just a few ounces off can damage the compressor over time.

I think the best thing to do to achieve a good, long lasting repair is to take it to a professional A/C shop that has the equipment and know-how to recover the charge, evacuate, add UV dye, and re-charge it to the proper weight. Then drive it for a while and see what it does. If the system's performance diminishes again due to a loss of refrigerant, then you'll have to take it back to the shop to have them find and repair the leak(s) and to re-charge it (again) to factory specs. Unfortunately, mobile A/C isn't very DIY friendly.