Working on my ac. System was dead with no charge. Replaced all O rings, drier, high and low side switch, orifice tube, compressor oil. Pulled a deep vac. The vac held for half an hour.

As I started to add refrigerant the clutch kicked in and stayed on. Got up to 26oz on a 32oz system. No cold air. Smoke started to come from PAG oil drips on compressor, I mean super hot!!!
Shut it down and let it cool. Now clutch just short cycles. Old orifice tube was not in terrible shape new one is of the variable variety.

Does anyone know if the clutch on this can slip and cause an overheat? Bad compressor, no strange noise or leak. Blocked up condenser? Bad orifice tube out of the box. All lines hot.

Any and all ideas welcome!
Thanks Jeff.

 

I'm not sure about the DIY kits out of a can, if they require the engine to be running or not, but it's generally not a good idea to have the AC system running as you charge it with refrigerant. Your PAG oil is carried through the system by the refrigerant. If you don't have enough refrigerant, it doesn't transport properly, and can starve the compressor of lubricant. If the cans instructed that the engine should be running when you add the refrigerant, it's because they don't expect you to have a pump to draw a vacuum with, and they do this under the notion that you're simply adding in order to top off a system which already has a substantial amount of refrigerant in it, not filling up a dry system.
The reason your compressor did not shut off is because it couldn't get to the pressure in order for the pressure switches to shut it off. You have a low and a high pressure switch. When the system pressure is below the set parameter, the low pressure switch will engage the compressor clutch, and it will not shut off until it reaches the cutoff point. Without enough refrigerant to build up that pressure, it's not going to shut off.
It all relates to why your lines are hot. Air conditioning works on a series of heat exchanges. This requires the refrigerant to absorb heat, become pressurized and superheated, then rapidly exchange that heat to the ambient air which passes through the cooling fins of the condenser. If the refrigerant is unable to do this, it'll experience a low superheat (or none at all), and it won't undergo a proper heat exchange. This can happen due to blockages in the system, inadequate refrigerant, an excess of refrigerant, excess PAG oil in the system, air/moisture saturation in the system... you have to be pretty close when measuring this stuff out.
Topping it off, it may also be possible that some of the refrigerant coming back into the compressor via the low pressure port is still in liquid form... did you replace the accumulator?
All refrigerant returned to the compressor on the low side needs to be in vapor form. To ensure this happens, AC systems will either have an accumulator (for an orifice tube system, such as the one in your vehicle) or a receiver-drier (in a thermal expansion valve system). It contains a desiccant, intended to trap moisture and prevent it from traveling further down the system to the compressor. When you open up an AC system, this desiccant becomes fully saturated within a couple minutes of exposure to ambient air - even in a dry state like Colorado or Arizona. The desiccant can no longer trap moisture, and refrigerant in liquid form will be able to enter the compressor inlet. In layman's terms, this is bad.
The bearings in the clutch, yes they can go bad. There's plenty of moving parts in the compressor which could go bad, whether it be in the clutch or in the compressor itself. Honestly, I'd have to look at it and see, but if I had to put money on it right now, I would lean towards damage caused by oil starvation, and the faulty component most likely to be in the compressor itself. This isn't to rule out the clutch, just calling it as I see it. How far did you isolate the source of the smoke?

 

Hey thanks for the time, yes brand new accumulator. Smoke was PAG spilled on compressor when I dumped it and replaced. Put in 8oz.
With low and high side not equalizing when cooled, low side almost nothing, I'm thinking heavy blockage in condenser or evap. Going to pull them and blast out with mineral spirits then lacquer thinner.
Think the rapid cycle was due to high switch popping, not ready to convict the compressor or clutch until I see what comes out.

Sound reasonable?
Thanks again, Jeff.

 

thinking blockage

 

I dont know if this will help, but here is a good walk thru:
A/C Overhaul/Compressor Replacement How-To - S-10 Forum

 

Thanks, think I made some mistakes as to too vigorous shaking of the can, one bad youtube can wreck your week, wallet also.