The 98 Chevy Blazer comes equipped with an air conditioning system that uses a more environmentally friendly refrigerant (Freon) called R-134a. Over time the seals in the air conditioning system lose their elasticity and, during cold weather, can shrink enough to leak small amounts of refrigerant. Adding additional refrigerant is a common repair that can be done by the average home mechanic in under an hour. An air conditioning gauge set (available at your local auto parts store) is required to complete the task.
Attach the gauge set to the service ports located on the a/c system. On the 1998 Blazer, the high pressure service port is located on the small diameter line near the passenger side fender well. The low side service port is located on the accumulator attached to the passenger side fire wall just behind the high side line. The R134a systems use a unique quick disconnect fitting on the service port. To attach the gauge set, pull the locking ring on the hose end, and snap the end onto the service port. The high and low side fittings are different sizes to eliminate the chance of miss-installing them.
Start the engine and set the air conditioning dash controls to maximum a/c with recirculating air, and medium blower speed. This provides the most accurate gauge and thermometer readings. Allow the engine to run for a few minutes so that the pressures displayed on the gauges are stable. Pressure readings under 35 psi on the low pressure side, and 200 psi on the high pressure side indicate a system that has leaked refrigerant.
Attach the refrigerant can tap to the yellow service hose on the gauge set. Slip a can of refrigerant into the can tap, and lock it into place with the thumb lever on the side of the can tap. Turn the thumb screw located on the top of the can tap all the way into the tap, and then allow the way out of the tap to open the can. Open the blue low-pressure side valve on the gauge set to allow the can to empty into the system.
Close the valve on the gauge set when the can is empty, and allow the pressures on the gauge set to stabilize. Add additional refrigerant until the gauge readings are above 35 psi on the low side, and above 200 psi on the high side.
