how to check for refrigerant leaks in my BMW 3 Series E90/E91 AC system?

Solution

1. Preparation

• Gather tools and safety equipment.
• Ensure the vehicle is parked on a flat surface and the engine is off.
• Wear safety glasses and gloves.

2. Visual Inspection

• Tools Required: Flashlight
• Inspect the AC compressor, hoses, and connections for any visible signs of oil or refrigerant leaks.
• Check the condenser and evaporator for physical damage or corrosion.

3. Use Electronic Leak Detector

• Tools Required: Electronic refrigerant leak detector
• Turn on the leak detector and scan around all AC system components, focusing on joints, seams, and any areas that show signs of oil or discoloration.
• Identify any areas where the detector indicates a leak, marking them for repair.

4. Soap Solution Test

• Tools Required: Spray bottle, soap solution
• Mix a soap solution (dish soap and water) in a spray bottle.
• Spray the solution on suspected leak areas and watch for bubbling, which indicates a leak.

5. Repair Leaks

• Parts Required: Appropriate seals, hoses, or components as needed
• Replace any damaged or leaking components identified during the inspection.
• Ensure all connections are tight and secure after replacement.

6. Recharge the AC System

• Tools Required: Manifold gauge set, refrigerant
• Connect the manifold gauge set to the high and low-pressure service ports.
• Vacuum the system to remove moisture and air, then recharge with the correct type and amount of refrigerant.