It is best to have the system tested for leaks, but if you really do want to add Freon, get a R134 can and hose kit from Kmart or Walmart, or Partsource. You need to be very careful doing this. Observe safety precautions. WEAR GOGGLES AND GLOVES and be VERY sure you fill from the low pressure side. You need to fill it from under the car, so if you can lift the front, or find a ramp or curb to let the front hang over, it's a little easier. Get under the car and find the compressor. The fill valve is close to the compressor. Unscrew the cap and judge how the hose will fit on. It's a tight fit. Now, get a 1/2 gallon pail of warm water (not hot). The freon flows best if the can is warmed. Mount the hose to the can, and start the engine and turn on the A/C to max. Verify the compressor clutch has kicked in. If it does not, the system may be too low and not engaging the low pressure sense switch. Probably best to get it checked if that's the case. If it is engaging, connect the freon hose to the low side fitting. Open the freon valve, and set the can in the warm water. After about 5-10 minutes, the can should be empty and floating. Close the freon valve and carefully (and quickly) remove the hose from the inlet. Let the freon circulate and check the A/C output. DO NOT OVERFILL the system. If it's still not cooling very well, you might try another can, BUT NOT MORE THAN the two. There may be other issues.
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