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John, Master Automotive Technician
Category: Car
Satisfied Customers: 9176
Experience:  ASE A1-A8 & L1 Master GM Tech 40 years experience
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2003 Pontiac Montana: the low pressure service port..freon

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Where is the low pressure service port on a 2003 Pontiac Montana. If posible. Need to recharge the freon.


The low pressure fitting is on the low side line comming off the compressor.If your vehicle a/c system is low & the compressor has been cycling enough for the computer to acknowledge this ,there will be a code & the compressor will not come on till it is cleared & system charged.

Customer: replied 8 years ago.
Reply to John's Post: I really need a diagram showing the location of the port. I can't seem to find its location.

OK,try this. Notice the valve on the line.

  • Recover the refrigerant from the A/C system.

    Important: Cap or tape the open A/C hoses immediately to prevent system contamination.

  • Remove the discharge hose to compressor nut.
    Object Number: 791658  Size: SH
  • Customer: replied 8 years ago.
    Reply to John's Post: Let me be a little more specific, I can't find the unit on the motor. Where is the compressor location, then the Low pressure port. Please enclose a diagram of engine location. Please be as specific as possible. I am in Arizona and its already 105 going up to 113 today. Thanks for your patience
    The location of the compressor is at the right front of the vehicle(under hood) down low.Open the hood & look down on passenger side of vehicle.Look at engine belt ,it leads to compressor.I honestly believe you should have a trained technician do this job.When you find the compressor ,look at the rear top,the lines go in there.Follow the line that goes to the back of the engine to locate the line tap ,it's not far from the compressor hook up.
    Are you still out thereCustomer?
    Customer: replied 8 years ago.
    I am trying to recharge with a can of sub-zero synthetic booster in a can. I think I located the port. Engine is too hot to hook up to now. I will try it in the evening. Have any suggestions for this. All would be appreciated.
    Be carefull not to get the hose up against the exhaust.A cool engine is helpfull.
    John and 3 other Car Specialists are ready to help you