The air temperture from my climate control wasn't as cold as it used to be so yesterday I put 2 cans of R-134a into the Low port and my psi with the compressor on afterwards was around 25 psi. (The AC has never been serviced before). Last night tempertures were in the 80s and the climate contol worked well. Today however, the temperture was higher (in the 90s) and my compressor kept turning on and off every few seconds. I googled my problem and it appeared I may have put too much R-134a in my system yesterday. So I rechecked the psi on the low side today when the compressor was on, it was over 45!!!! (it was around 25 yesterday!....I don't understand how it could have increased since I checked it yesterday!!). How can I remove some of the excess R-134a? (I'm not mechanically inclined....can I stick a pointed object in the Low port for a few seconds so that some of the R-234a is released and the psi goes down?

I also just found this: http://www.nicoclub.com/FSM/Maxima/1995/ha.pdf It appears to say that at 95 degrees, that the lower psi should be between 23 and 27 (on HA-31 page 957)....does that sound correct? Thanks in advance for any suggestions.

 

You could do that. The cans are r134a equvilant but not actually r134. You were obviously losing refridgerant for a reson. The cans are o.k in a pinch but it's best to have the system hooked up to a vacume pump before charging to remove any moisture or contaminants. Basically you want to pressurize the system with nitrogen to see if you have a leak at which time you spray all the conections with soap and water watching for any signs of bubbling or charge the system with dye. If you have no leaks then hook it up to a vacume pump for approx. 45 minutes then charge the system.

 

You can take care of your overfill problem the same way you let too much air pressure out of a tire. The atmosphere and the world will not end because you do.


Just let some out, and see what happens.

 

Doesn't FSM say that 45-52 psi at that temp is the proper range?

 

The pressure will change based on the temperature. My filler hose has a gauge on the top that tells you what pressure it should be based on ambient temperature. 45psi wouldn't stand out to me as too high. Cycling on and off was always a sign of low pressure to me. I have never overfilled a system. Hook up the can, press lever until can is empty, drive.

 

Did you use a kit with the gauge installed on the can? You're supposed to adjust the temp setting according to the real temp during the recharge. This should also tell you when the system is fully charged or not.

 

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OP, did you account for temperature? Did you add the freon while the car was on, AC on/compressor running?

Put just the gauge back on the low port and see what reading it gives you. Maybe you have a leak and it all leaked out already.

 

The FSM should mention specifically how much R-134 you need (last page, 138 mentions 0.800kg or 1.764 lb) ... Also, 45 on a 90+ day is normal. When it gets hotter, the pressure will increase and this is normal as others have stated. I would just let some out in the atmosphere but be careful not to breath it or have your face near it as it can cause serious damage...


I would check for leaks and there are several ways to do this. My preferred method is to get some R-134 with UV dye, UV light and shine away in the evening when it is getting semi dark. If there is a leak it will glow like a neon green color.