Automotive Air Conditioning Information Forum

The 94 Civic was completely empty of Freon so I ran a vacuum overnight the following morning I put a can of 134a Freon in it started filling it up and seem to get about 3/4 away from emptying the can and that point didn’t seem to be taking anymore so I jumped the pressure switch to ingage compressor in hopes that the suction would actually pull some of the Freon in it didn’t really seem to make that much difference. when I revved the engine I couldn’t see the gauges fluctuating at all the head pressure line at the condenser was very hot and indicating that was there was some compression going on with the gases
75 suction and about 60 head. Suction line was not cold. The car holds 19 oz of freon I didn't even in make it through a 12 oz can.

With the compressor engaged
75 suction and 75 head

Where do I go from here. The ac has not been used in the system in years all original parts. I have seen these compressors last over 300k my car has 221k

thanks
help would be appreciated

Presuming that you have your Manifold Gauge Set connected correctly, the compressor is running, and you're charging refrigerant vapor (can upright) into the low side (with both the low-side adapter and MGS handwheel fully open, and the high-side MGS handwheel fully closed), then the refrigerant should flow into the system with ease. Of course, refrigerant WILL NOT flow into the system with a low-side pressure of 75 PSI, which is about equal to the pressure in the can.

Did the system hold the vacuum for an hour or so after evacuating it? If not, the system has a leak.

I don't recommend "jumpering" anything to force the compressor to run. Otherwise, you run the risk of ruining it.

thanks for your response.. vacuum pump was run overnight and it held for an hour before I attempted to charge. Initially system took some charge, but the compressor was not running because I assume the pressures were to low to complete the circuit on the pressure gauge located on the highside of the condensor more so I jumper-ed the pressure switch to see if the suction side would pull in more freon, but it didn't seem to make a difference. Seems like there might be a restriction in the system, perhaps rec dryer or expansion valve or perhaps the compressor is so weak it is not able to create enough suction to pull in freon. One would think that if the freon is low that the suction side pressure would be also ?( can be co low evap freezes up)

At his point I am ready to just throw parts at it ?? Compressor,Exp Valve ,Dryer and condenser. Comments?

If you had a restriction at the TXV, chances are you'd see very low pressure on the low-side of the system, or the low-side might even pull into a vacuum (presuming you could get the compressor to run). In this instance, my guess is that the TXV has failed in the open position, which would cause the pressures on the low-side and high-side of the system to be about the same and result in its failure to take a full charge.

That being said, the scroll-type compressor (which is what I believe your Civic has) probably is tired with ~221K miles on the car and the A/C system not having run in years.

Given this system's history, I would replace the following components: Compressor and clutch (new, not rebuilt); condenser; TXV; and receiver/dryer. If it's not too difficult to access it, I would also replace the evaporator. If it's not easily accessible, flush it in-situ a few times (remove the TXV beforehand), being sure to evaporate-out all traces of the flushing liquid.

Then examine all the lines and hoses. If they appear to be in good shape, flush them as well and reinstall them. If there's any question as to their integrity, replace as needed. Note that any lines with mufflers can't be flushed and must be replaced.

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Don't forget to add the correct amount and type of oil before evacuating and charging the system.

According to the specs that I have, your Civic takes 19 ounces net weight of R-134a and 5.0 fluid ounces of PAG-46. If the under-hood decal—which takes precedence—says differently, go by that instead.