my BMW 3 Series E90/E91 is making a popping noise when I turn on the heater, what could it be?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.

2. Remove Cabin Air Filter

• Locate the cabin air filter housing (usually under the dashboard on the passenger side).
• Remove the cover by unscrewing or unclipping it.
• Take out the old cabin air filter; check for debris or damage.
• Replace with a new filter if it is dirty or clogged.

3. Inspect Blower Motor

• Access the blower motor by removing the lower dashboard panel.
• Disconnect the electrical connector and remove the blower motor using appropriate socket sizes.
• Inspect the motor for debris or foreign objects.
• Clean any obstructions and ensure the motor spins freely.

4. Check Heater Core and Ductwork

• Locate the heater core hoses in the engine bay; inspect for leaks or damage.
• If accessible, check the heater core for signs of blockage or corrosion.
• Inspect the ductwork leading to the cabin for any obstructions or blockages.

5. Reassemble Components

• Reinstall the blower motor and reconnect the electrical connector.
• Replace the lower dashboard panel securely.
• Reinstall the cabin air filter cover.
• Reconnect the battery.