Automotive Air Conditioning Information Forum (Archives)

Provided by

We've updated our forums!
Click here to visit the new forum

Archive Home

Search Auto AC Forum Archives

High on the high and low on the high

chmitchell on Mon February 02, 2009 9:18 PM User is offline

Year: 1992
Make: toyota
Model: camry
Engine Size: 2.2
Refrigerant Type: r134a
Pressure Low: 80
Pressure High: 80

Ok where to start. Been working on my camry for bout 8 months now. compressor went bad (clutch). replaced it along with expansion valve and drier. Since i had system open and don't know what the previous owner had in there i flushed it out (had UV dye and prob some type of sealer) Flushed the hoses good and blew and dried them out. I put everything back together with new o-rings. Pulled vacum and let it hold for a day to check for leaks. Started charging system filled high side with liquid just enough to cut compressor on. then done the normal vapor on low side. Thats when i noticed the high side would not go above 90psi and low side would fluctuate a little check compressor it is engaged and running. Figure compressor bad, returned it and put another one on same thing. Recovered and changed the expansion valve again figure it might be stuck open. Still got bout the same readings when running. getting a static reading of 130psi low and 70psi high. any help would be greatly apprciated. Just trying to get a jump b4 summer gets here. thanks sorry for being so long but wanted to give as much detail as possible.

Chick on Mon February 02, 2009 9:42 PM User is offlineView users profile

when reading your pressures are you sure the wheels are turned off on the guage set?? Try the guages on another car that is working? Depending on where the high side port is, you could have a blockage in the drier, condenser etc.. Could be pooling the refrigerant in the condenser..Feel the lines going in and out of the drier, are both lines the same temp, lines in and out of the condenser, line coming out cooler? Hot going into the condenser? You didn't flush thru the drier or expansion valve did you? You might find this repair manual very helpful in diagnosing your system. It's very odd both compressors are doing the same thing, so if have to check everything, also the amount you put in.. Has to be around 75 to 80% of the R12 charge.. Not enough will give you weird pressures..Hope this helps..

Email: Chick


Freedoms just another word for nothing left to lose

bohica2xo on Tue February 03, 2009 2:40 AM User is offline

Chick covered all of the big stuff, but I can add one small thing...

134a conversion. Check to see that your high side fitting is actually depressing the schrader valve. With the system running push down on the high side connector, and watch the gauge. Your static readings show a low pressure on the high side - is that about the same as the static pressure in your charging can?

A schrader valve will act as a check valve, and you can charge through one that is not open. You wind up reading the pressure in your hose - which is usually the static pressure when you connected it. There is just enough slop in some of those conversion fittings that the valve only gets depressed when the connector over-travels during connection.

Some service connectors have adjustable valve depressors, others are fixed. Sometimes a cable tie around the assembled coupler & service port will do the trick.


"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

mk378 on Tue February 03, 2009 10:49 AM User is offline

It's almost impossible for the low side static pressure to ever actually be higher than the high side, so I would agree that it sounds like a measurement or fitting problem. Use the steel conversion fittings with their own shrader valves (not the aluminum ones found at chain parts stores) and take the stock shrader valves out of the R-12 fittings before putting the converters on.

Did you have close to the proper amount of refrigerant in? Was it getting cold at all?

chmitchell on Wed February 04, 2009 8:00 PM User is offline

Thanks for your responses
I'll check the fittings but don't think it was the conversion fitting. When pulled to vacuum high side also went down. I have on the hoses are quick connect with the screw down (MAC gauges). Also see pressure change when I engage clutch off and on. I'll double check everything this weekend suppose to get in the 60's. If it is a bad connection they why isn't the low pulling into a vacuum? As for the amount of 134a it will only take bout 16oz. and then no more. Suppose to hold for some reason i wanted to say 36oz of R12 so it should be 28oz. roughly. The air coming from the vents is barely below ambient temp. maybe 5 degrees. The outlet on evaporator is cool but not cold to the touch. Went as far as taking the cover back off evaporator to see if it was icing up but it wasn't just cool the to the touch. Again thanks for the help.

Edited: Wed February 04, 2009 at 8:12 PM by chmitchell

Back to Automotive Air Conditioning Forum

We've updated our forums!
Click here to visit the new forum

Archive Home

Copyright © 2016 Arizona Mobile Air Inc.