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kuehl kuehl is offline
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Join Date: Aug 2004
Location: Stuck in NJ
Posts: 3,091
Best way to test your service manifold and service hose set is to pull a vacuum on an empty 30 lb refrigerant can. Ideally you want a 4 valve 4 hose service manifold: low side, vacuum, refrigerant and high side. Pull down to say 200 microns if you can. Close your vacuum valve. Don't be surprised to see the micron level rise to 500 microns within a minute or so, then it should level out.

"40 Psi on low side and low 300's on high side after just 2 12 oz. cans and vent temps only about 60 degrees."
At what ambient air temperature around the car?
Was the rear deck lid down resting on the service hoses?
Is the front condenser blower motor running?

"They pulled out the r134 and vacuumed it down then put about 44 oz of R134 and got same results as me....42 psi on low side and vent temps about 60 degrees."
42 psi on low suggests an evaporator temperature of 47 degrees. A delta of 13 F degrees between the vent and evap core .
Stick a digital thermometer in the evap core to observe what its temperature is.
In general terms, with a normal operating system your evaporator outlet hose fitting will be sweating or frosted on a good system.
If your evaporator core is near freezing and you are seeing much higher vent temps then inspect for air leaks between the plastic evaporator outlet tube and the center vent.
1987 911 cab, modified

Last edited by kuehl; 07-09-2018 at 10:57 AM..
Old 07-09-2018, 10:09 AM
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