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A/C compressor making BAD noises


NAXJA Forum User
So yesterday I decided to re-charge my a/c system. It was so low that the compressor wouldnt cycle. So I put in a 13 oz. can of r134a with leak sealer. Then it started making all these noises. So I thought maybe it needed some oil. In went a 8 oz. oil charge. Still noise and a good bit of vibration. A look at the sight glass shows foamy refrigerant passing by. Does this mean i need to add more refrigerant? That's what the hayes book says...but I dont trust it. Also, when adding refirgerant to a converted r134a system (this is an 87 XJ), do I put gas in it or liquid in it? Basicly, do i hold the can right side up or upside down when charging the system?
MOre r134

Bubbles in the sight glass means you need more charge. It is recommended to remove all the r12 before servicing but I have put r134a on top of it with no bad effects. When you put in r134a in a r12 system your low side pressure should be about 10% less than normal for r12. My can reccommends turning the can upside down above the low pressure port. As for your noises, when was the last time you had it running? I would be concerned because none of the cars I have serviced changed sound when I replaced the refridgerant. The compressor might have seized up from non-use.
actually, i figured it out. Well, kinda. The compressor isnt making noises at all. The belt where it runs below it is vibrating side to side. It only does that when the a/c compressor is turned on. The belt it a little tighter than it should be, but the problem still exists. It vibrates side to side as in the same direction as the front bumper, not front to rear. Any ideas? I'm going to get a new belt because the old one has some cracks in it anyways. We'll see if that helps because it seems to be a harmonic vibration and changing the belt might fix that.
Harmonic balancer

Check your harmonic balancer and see if it has migrated. Change if neccesary. Good luck.
I've got the same problem... filled the old system up and now the compressor is making angry noises. Is it "loading up"? My bearings might be going too, the belt couldn't turn (smokin) the compressor today... some of the R134 "escaped" shortly there after :shhh: and it then turned freely and somewhat quieter. If somehow there was another accidental escape would that solve my problems?
Depending on which compressor you have, they can be overfilled. When the clutch engauges watch the site glass, it will fill up quick, then fall a little. They say to keep filling until the site glass, stays full, when the clutch is engauged (or with just a few bubbles). But I always leave mine just a little low, pressure is probably going to go up some, as the summer progresses. An overfull system, can have a full glass, which can appear empty (freon is clear). Emptying the system (put it in vacume) and adding the appropriate wieght of freon, is always the best solution. A few odd bubbles or foam, rarley degrades the cooling much, but if much air is mixed in the system, it will push your pressures up to unacceptable levels. Always purge the lines, with a little squirt of freon, before hooking them up. Make sure the hose ends are dry, moisture will mess up the system. Putting the freon, fill bottle, into a bucket of hot water and filling slowly into the low side, only when the clutch is engauged, works for me. With the compressor clutch disengauged, the low side pressure can go higher, than the filler tank pressure, you can push freon back into the filler bottle. Only open the valve a little, so you can shut it off quick, if the clutch disengauges. Jumping the clutch or pressure switches, for continious run, is dangerous. Anything over say 350 PSI can rupture the lines (goes off like a grenade), pressure builds from 250 to 350 in seconds, if a line becomes plugged. The rated burst, is some higher than 350, but it´s good form to plan for the worst.
Most systems have a high pressure switch, that will shut of the clutch, when the pressure gets too high and/or an internal bypass. Both often make a pop. pop, pop sound, when the compressor is over full.
I often, feel the low pressure pipe, near the compressor, when it starts to get cold, thats usually enough freon or darned close.
The freon level in the system is like a bell curve, not enough freon, too enough freon (by wieght) (peak efficeintcy)and then the efficientcy starts to fall off again, with too much freon, as the liguid to gas change (peak cooling), gets pushed into the engine compartment (where it doesn´t do much good).
Filling the system on a hot day, with the doors open and the fan on high, usually works out the best. Helps keep the compressor from cycling, to often and makes overfilling unlikely. After you get, close, you can shut the doors and watch it cycle a few times.
If you have a gauge, the low pressure rarley goes above 25 PSI (R-12) and the high pressure max is around 250 (R-12), or somewhere between 200 and 250 (it changes with system load and outside air temp.). If you hook up a high pressure gauge, be carefull, the hose is under quite a bit of pressure, the liguid gas in the high pressure hose can burn (frostbite) your fingers. Keeping the gauges above the level of the compressor, will help keep oil out of the gauge hoses. The oil level, on the compressors with the freon, mixed with oil, isn´t real critical, between say 4-6 OZ. If it hasn´t all leaked out, I wouldn´t bother with adding much. You usually have to dismount the compressor and turn it upside down to get most of the oil out (of the oil integrated) compressor, the york is different (it has a seperate crankcase oil supply).
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I kinda figured it was overfilled... More freon mysteriously escaped the system today :D and things have calmed down now. I'll mess with it some more this weekend. Feel free to hop on the next flight to Florida and help ;)

Thanks Mud!
Was toping off mine the other day, got to BSing with a buddy and over filled it. To much gas, often overheats the compressior, have heard of the front seals going. 300 PSI or so, can get the compressor, to hot to touch, the hot compressor heats up the freon and drives the pressures up even more. Kind of a slippery slope to catastrophy.
If you have to bleed of a little freon, do it on the low side and slowly, give the system some time to stabilize. Check the site glass often.
Most of the A/C´s I mess with, are bigger than your XJ, but the theory is pretty much the same.