Ok, I have a 95' civic ex. It wasnt blowing cold air so i added a can of r134a, after about 10 min. the compressor was cycling on/off every sec. or two then it sprayed the oil/freon out the relief valve on the compressor.

The clutch is working, when i turn the ac on the clutch engages, but it never dis-engages. It will blow cold air as cold as 53deg. but will flutuate from 54 to 76 deg., i hooked up one of those cheap $10 pressure guages to the low-side and it was at 55psi. Any ideas??? Thanks

 

It appears that you overcharged it. Total capacity from fully empty is only 18 oz (1.5 cans).

Check that the relief valve is not leaking; sometimes they don't re-close fully. Then you need to evacuate the system and recharge with the proper amount by weight. If you don't have the tools to do that, have a shop do it. You may want to add a little PAG 46 oil to replace that which blew out, but realize the total oil capacity is only 4 oz and too much oil will really hurt performance.

Then once you know you have the proper charge you can measure both pressures and diagnose the problem. Temperature and pressure fluctuating around suggests a balky expansion valve.

 

The normal pressure range for the low side is 22-36 PSI, so you definitely overcharged the system with refrigerant. By the way, the normal pressure range for the high side is 220-295 PSI.

 

ok thanks, i will have it evacuated and recharged. just curious though, shouldnt the compressor not engage if its overcharged??

 

It takes a few seconds for the refrigerant pressure to reach its maximum after the clutch engages. When the pressure becomes above the set limit for the pressure switch, the compressor is switched off.

 

ok, so does that mean my pressure switch may be bad? Cause the compressor never shuts off while the ac is on.

 

Cycling every second, the switch may not have been able to act fast enough. Now some of the pressure has been released. In normal operation, the compressor will run constantly until the air inside is fully cold (about 40F with the dash control on cold).

Hopefully you didn't add anything containing "stop leak." These products can clog up your condenser so the pressure at the switch (which is after the condenser) is normal but it is very high at the compressor.

 

You can't just randomly add refrigerant to the system. Please do not mess with it if you do not know what you are doing.

Get the evac/recharge done at a shop.

 

so i had the system evacuated and vacuumed..its held a steady vacuum for about 15 min.
the ac doesnt change temp. as drastic now, it will stay a steady 54-56deg. i know thats alot better than it was but i also know it should prob. be 46-48 deg.
my mechanic said it could possibly be a weak compressor from what he was seeing on the guages..

 

Check that your heater control valve closes fully with the dash lever on cold. The heater may be fighting with the A/C. Temperatures in the 50's are typical when idling on a hot day. It should go down when driving though.

What pressures did he see on the gauges?

Pulsation of the high side gauge is normal with the scroll type compressor used in the Civic.