why is my BMW X3 F25 (2011-2018) AC blowing hot air instead of cold

Solution

1. Preparation

• Gather tools: OBD-II scanner, manifold gauge set, refrigerant, socket set, screwdrivers, and safety goggles.
• Disconnect the vehicle battery to ensure safety during repair.

2. Recharge Refrigerant

• Step 1: Connect the manifold gauge set to the low and high-pressure ports of the AC system.
• Step 2: Check the pressure readings on both sides; if low, proceed to recharge the system.
• Step 3: Use the appropriate R-134a refrigerant to fill the system slowly while monitoring the pressures to avoid overcharging.
• Step 4: Once the desired pressure is achieved, disconnect the gauges and reconnect the service ports.

3. Inspect and Replace AC Compressor (If Necessary)

• Step 1: If the compressor is not engaging, remove the drive belt by loosening the tensioner.
• Step 2: Disconnect the electrical connector from the compressor and any AC lines connected to it.
• Step 3: Remove the compressor mounting bolts using a socket set.
• Step 4: Install the new compressor by reversing the removal steps; ensure it is properly aligned and secured.

4. Replace Cabin Air Filter

• Step 1: Locate the cabin air filter housing, usually behind the glove box.
• Step 2: Remove the glove box or cover to access the filter.
• Step 3: Take out the old filter and insert the new one in the correct orientation.
• Step 4: Reassemble the glove box or cover.

5. Verify System Functionality

• Step 1: Reconnect the battery.
• Step 2: Turn on the AC system and set it to the coldest temperature to check for cooling.
• Step 3: Monitor for any unusual noises and ensure airflow is consistent.