A/C Compressor cycling, Air still cold

[Owebs]

Ever since I changed my timing belt (which required me to unbolt but not remove my A/C compressor):

- while idling, my compressor has been cycling every 5-10 seconds causing my rpms to drop each time (freeway speeds there is no drop)

- my A/C still blows cold, my heat still blows hot

I bought a can of refrigerant (I thought it was cycling because it was low), but the gauge on the refrigerant says the pressure is high so I ended up not putting any in. Its not an accurate gauge but it is showing up at the top of the red zone.

I noticed that when I put the gauge on to get a reading and then take it off the port makes a quick hissing noise (just like taking a tire pressure gauge off), then the compressor stops cycling and my rpms are stable again, until I give it gas. As soon as I give gas, it starts to cycle and my rpms drop each time.

Now while driving I only use my air or heat while at speed, and whenever coming to a stop I am forced to turn it off or have my rpms constantly drop.

Before I changed my timing belt the compressor did not cycle at such a high frequency. Any help would be appreciated! Thanks!


1997 Ford Ranger 2.3L

[Jswifto]

Do not forget the ac cycles on your defrost settings also. That should be the last two settings on the dial.

[B2300SE]

I'd have to check the diagram, but the system may have a high pressure limit switch and it might be "tripping" because the pressure builds too high after it runs for 10 seconds. That means the system is overcharged, there's an obstruction somewhere (like a clogged filter screen), and/or the pressure switch is bad.

There's also a thermal switch on the evaporator by the heater core that keeps it above freezing. If the outside air is cold (less than 50 degrees) it will trip fairly quickly but in warmer weather the compressor should run longer.

Buy a set of A/C gauges or take it to a shop that will put their gauges on it for free. If it's an obstruction the system will have to be opened up and diagnosed. The Ford compressors are sadly know for what's called "black death" where the seals in the compressor disintegrate and the crud gets circulated throughout the system clogging things up. They can still cool, at least for a while, while the compressor is destroying itself and contaminating the entire system.

The main cause of black death is running the system for an extended time with too little charge. The lube oil for the compressor is in the refrigerant. So when the charge is low, so is the lubrication and the seals on the compressor pistons self destruct. Hopefully that's not your problem but it's something to be aware of.