AC system PAG oil capacity (1 Viewer)

[SimpleTruth]

I am trying to clarify the pag 46 oil capacity for the total ac system. This is for a 2000 model year lc100 with both front and rear evaporators and a central coolbox. The workshop manual states that 1.4 fl.oz (40 cc) should be added when any of the evaporators are replaced. If the condenser with receiver/dryer is replaced then it needs 1.7 fl.oz (50 cc) to be added to the system. This is a total of 5.9 fl.oz (170 cc) without counting the compressor.

The rule for replacing the compressor is to drain the oil from the old one and measure the amount. The new compressor should also be drained and the same amount of oil, as measured previously, should be returned. The new compressor should now have the same amount of oil as the old one had. This assumes that the old compressor was working properly and the oil is properly distributed around the ac system. Unfortunately, this isn't usually the case. There is no listing in the manual for either total system capacity or compressor capacity. If the system needs flushed after a failure and the condenser and compressor are replaced then the full system capacity should be known.

The manual lists the oil in both cc and fl.oz values. It also says that measurements are based on SI UNIT (International System of Unit), and alternately expressed in the metric system and in the English System. This makes sense for the values of torque settings in diagrams but is the fl.oz really a fl.oz(uk) or fl.oz(us)?

DENSO lists their replacement compressors as containing a charge of 220 cc. It would make sense that this was a full system charge otherwise extra oil should be purchased. This would leave 50 cc (220-170) for the compressor. This is only 1.7 fl.oz. I don't think the compressor would have only this amount. If there were no coolbox then the compressor would get another 1.4 fl.oz for a total of 3.1 fl.oz. The last option is for a front ac only then the compressor could have a total of 4.5 fl.oz (130 cc). Take your pick!

From what I've read, people are adding back 4 fl.oz to their compressors after draining. In my case that would result in a total oil capacity of 9.9 fl.oz. Can someone please confirm my conclusions.
Sorry for the long post.

 

[JunkCrzr89]

Post in thread 'A/C servicing; vacuum, oil and charge system?'
A/C servicing; vacuum, oil and charge system? - https://forum.ih8mud.com/threads/a-c-servicing-vacuum-oil-and-charge-system.1055725/post-11894997

@flintknapper is probably the best person to answer your questions.

 

[flintknapper]

I am trying to clarify the pag 46 oil capacity for the total ac system. This is for a 2000 model year lc100 with both front and rear evaporators and a central coolbox. The workshop manual states that 1.4 fl.oz (40 cc) should be added when any of the evaporators are replaced. If the condenser with receiver/dryer is replaced then it needs 1.7 fl.oz (50 cc) to be added to the system. This is a total of 5.9 fl.oz (170 cc) without counting the compressor.

The rule for replacing the compressor is to drain the oil from the old one and measure the amount. The new compressor should also be drained and the same amount of oil, as measured previously, should be returned. The new compressor should now have the same amount of oil as the old one had. This assumes that the old compressor was working properly and the oil is properly distributed around the ac system. Unfortunately, this isn't usually the case. There is no listing in the manual for either total system capacity or compressor capacity. If the system needs flushed after a failure and the condenser and compressor are replaced then the full system capacity should be known.

The manual lists the oil in both cc and fl.oz values. It also says that measurements are based on SI UNIT (International System of Unit), and alternately expressed in the metric system and in the English System. This makes sense for the values of torque settings in diagrams but is the fl.oz really a fl.oz(uk) or fl.oz(us)?

DENSO lists their replacement compressors as containing a charge of 220 cc. It would make sense that this was a full system charge otherwise extra oil should be purchased. This would leave 50 cc (220-170) for the compressor. This is only 1.7 fl.oz. I don't think the compressor would have only this amount. If there were no coolbox then the compressor would get another 1.4 fl.oz for a total of 3.1 fl.oz. The last option is for a front ac only then the compressor could have a total of 4.5 fl.oz (130 cc). Take your pick!

From what I've read, people are adding back 4 fl.oz to their compressors after draining. In my case that would result in a total oil capacity of 9.9 fl.oz. Can someone please confirm my conclusions.
Sorry for the long post.

I am not familiar with the total system requirement where there is a 'cool box' involved, but I agree with your assessment that something between 9.5-10.0 fl. ozs is likely very close to correct. IF you have the 10PA20c Compressor it will take about 5 ozs by itself.

While we strive to have an accurate amount of lubricating oil.....there is a little room to 'fudge' without worry.

You would need to be grossly over charged (2 ozs or more) for it to have a negative effect on cooling and likewise undercharged to significantly shorten compressor life. I would be quite comfortable with the figure you have arrived at for the total system.

 

[SimpleTruth]

I am not familiar with the total system requirement where there is a 'cool box' involved, but I agree with your assessment that something between 9.5-10.0 fl. ozs is likely very close to correct. IF you have the 10PA20c Compressor it will take about 5 ozs by itself.

While we strive to have an accurate amount of lubricating oil.....there is a little room to 'fudge' without worry.

You would need to be grossly over charged (2 ozs or more) for it to have a negative effect on cooling and likewise undercharged to significantly shorten compressor life. I would be quite comfortable with the figure you have arrived at for the total system.

Thanks for the good advice. As you said, the compressor is a 10PA20c and the cool box is located inside the center console box. The liquid and suction lines are just connected to the lines going to the rear evaporator. This lc100 is a GCC model and has a few differences. The compressor has a thermal cut out in the top valve manifold. It is wired into the clutch circuit and will disable the clutch if the compressor gets too hot. Also, there is no rear heater circuit so no problem with a plastic heater 'T' failing.

I will go with the oil levels that I had already chosen and appreciate your confirmation of my calculations.