2drEG

so i bought some r134 for my car, thinking it was low on freon. When i started my car and turned the a/c on, it started to blow hot air, so i checked the pressure gauge, and it showed at 150 p.s.i. on the low side. i'm thinking a new compressor. idk if it is indeed what i need, but also when i turn the a/c on it will bring the rpms up and then drop them rapidly, probably 2-5 second intervals. any ideas? thanks guys...

pk386

(the Enter Key is your friend) ;-)

Does the Clutch engage on the ac compressor?

-If the ac compressor engages and the PSI drops to 25-45 psi that's normal.

-If the ac compressor engages and it stays at 150 psi. you got serious issues turn the ac off immediately and get help from a friend in the ac business.

the Idling issue is normal (basically when you turn on the ac the ECU ups the idle speed to compensate from running the ac)

Former User

I think the normal low side pressure is 22-36 PSI. What was your high side pressure? Knowing the numbers on both the low and high sides will tell you whether the system is overfilled or has a different problem. Nonetheless, given that you just added refrigerant, I think you likely overfilled the system. In this case, you need to drain the entire system, evacuate it, and then refill it to the proper pressures.