What is the proper a/c pressure reading for a mazda 3 while the a/c is on full and the car is warmed up.

I've been having issues with the compressing going on and off while driving and figured it was low. The gauge read 25psi but it doesn't seem to take anymore refrigerant if I try to add any.

Thanks

 

baaaaaaaaaaaaaaaaaad move, adding more ref just because it dont get cold or dont stay cold is a huge no-no, the compressor is supposed to cycle so the pressures dont rupture line and fittings. i hope that you didnt add ref that had sealant in it, if you did be prepared to end up replacing your whole a/c system in a few years (maybe)

Normal pressures on the low side is 25psi depending on outside air temps

 

I only added a small amount of standard r-134a with no sealant , it was a cheap can from walmart. I thought the compressor might cycle off if the pressure was too low. The pressure readings in that chart are really low should I attempt to let some out to bring it down?

 

Nope. All that you will achieve is freezing some fittings. Take it to have it serviced and they will give you an exact rundown of what the problem is.

For future reference, add only when the pressure is low and the compressor is pumping. If the pressure is normal and it is still hot, there is another problem.

 

Partially true. A low pressure on both high and low sides of the system indicates the need for refrigerant. Most of these "recharge kits" only connect to the low side and thus don't show you if the high side pressure.

In fact, a blockage in the system can cause a low side pressure low and a high side pressure high.