We tried adding freon to our 98 Montero AC unit but when we attempt to it says the it is at full pressure and will not let us add any but it is only blowing hot air with the ac on, so we do not think it...
Hi, if you have full pressure (40-50 PSI on low pressure side with engine running A/C set to maximum and blowing) you have enough pressure, but there is air in the system which degrades the refrigerant leading to no cold air. To remedy this, you must completely discarge the system and refil with new R134a which has the compressor/system oil added to it.
To discharge the system, shut off motor, attach your filler hose to low pressure valve and allow system to drain. (squeeze handle if you have that type filler hose) Allow it to drain until no sound of escaping air is present. Be careful not to have the end of hose facing you or others, wear gloves and have some shop rags laid down, pointing nozzle toward rags, that stuff can damage paint and skin and may be cold when escaping. After system has completely drained, start the refil process with engine running, A/C on maximum, blower on full. After about 1/2 of the first can of R134a or 1 full can, your compressor should kick on. Continue refilling with 3-4 cans total (about 3 LBS total) until you have a reading of 45 or so PSI. After each can, allow refrigerent to cycle through the system about 3 minutes to obtain an accuret pressure reading. Pressure is relavent to outside temperature also, optimumly the ambient air temp. outside vehicle should be between 72 and 80 degrees F. for proper reading. That should get you blowing cold air again!
Please rate this answer! Thanks, Mike
Jun 14, 2011 |
Mitsubishi Montero Sport Cars & Trucks