AC blowing warm air and intermittent compressor engaging
 

I'm servicing my Mother's car right now and the AC blows warm air when on Max and high fan speed, and the compressor seems to be cycling weird. With the engine turned on and Max AC is running at high fan speed the compressor clutch engages spinning for about 10 seconds, and then it disengages and stops turning for about 10 seconds. It keeps doing this on and off deal until the AC is turned off.

Is what I'm seeing consistent with low freon/R-134a?

Her car did this last spring and I added some refrigerant and the AC began to blow cold again, although I'm not sure if the compressor was behaving this way last time.

Yes, a low refrigerant charge will do this.

Thanks hanky. I got some gauges on and it was reading 70 lbs on the high side with the RPM at 2000. So I hook up an 11 oz can with a cheap removable gauge (only colors, yellow low, green good, red high) to the low side and tilt it over to add with the AC on Max and full fan. It didn't pull that much in it seemed, so the second time I tipped the can over I held it just a little bit longer and I think it sucked just about the whole can in, and the pressure meter red WAY into the red, high. I think it seized up the compressor because smoke started coming from the compressor pulley? possibly, from that area anyway. I turned the engine off immediately and released some of the refrigerant from the low side. I think what happened is that the pressure was too high in the system and the compressor wouldn't turn, so the compressor pulley stayed in place when the clutch was engaged and the smoke came from the serpentine belt running past the compressor pulley with it not turning. Best guess anyway.

So now I don't know what to do. What I'm thinking of doing is having all the refrigerant taken out, putting a vac pump on and evacuate the system and start from scratch. The sticker under the hood says it takes .96 kg of r124a, which is 33.86oz which is just .86oz over exactly 3 x 11oz cans of refrigerant. Best idea so far.

Hopefully my compressor isn't shot.

Any thoughts?

Bradley,,,,,,you did something you don't want to do when adding refrigerant.

The compressor pressurizes GAS refrigerant ONLY !!! Never add liquid to the system it can destroy the compressor.
Lets hope it is not damaged.
NEVER TURN THE CAN OF REFRIGERANT UPSIDE DOWN WHEN ADDING TO THE SYSTEM THAT SENDS LIQUID TO THE COMPRESSOR IF ADDED ON THE low SIDE.
Maybe the refrigerant stabilized some and the compress might still work, don't know. If it does, you add refrigerant gas to the low side and allow the compressor to compress it and send it to the condenser to be cooled and then sent to the accumulator and on to the orifice then on to the evaporator inside the vehicle.
If it still works , you are lucky !
Let us know how you make out with this , OK ?
You keep adding GAS until the low side pressure comes up to approx 30 psi and stays close to there. If working correctly the compressor will keep cycling until the charge is sufficient. It should cycle one or two times a minute approx. If you are using a set of manifold gauges you will notice at the 30 psi mark the temp is just above freezing..

Thanks for the advice hanky. I'll never turn another can sideways again

I evacuated the system with a vac pump and I'm ready to add refrigerant now. Another poster on a different board asks...

'Are you sure it's not 34oz. of r134a and 7oz. of pag#46 oil??? '

Do I need to worry about adding oil? I would think it's still in the system being no components were taken apart. Here's the refrigerant sticker under the hood...

https://cimg8.ibsrv.net/gimg/www.for...05652814f4.jpg

Unless the oil leaked out with a leak, there should be no need to add any at this time.

Very small seasonal leaks usually only lose refrigerant.