How to replace BMW E46 318Ci (N42B18) window regulators?

[spinecki]

How to replace BMW E46 318Ci (N42B18) window regulators?

Tools needed:

• Torx T30 driver
• Flathead and Phillips screwdrivers
• Plastic trim removal tools
• 10mm socket and ratchet

Replacement procedure:

• Remove door panel (be careful of wiring connections)
• Disconnect window from regulator
• Remove old regulator (typically 3 or 4 10mm bolts)
• Install new regulator (OEM part number: 51337020660 for front left)
• Reconnect window to new regulator
• Test operation before reinstalling door panel
• Reinstall door panel

Tips:

• Apply silicone lubricant to window channels for smoother operation
• Consider replacing both sides even if only one has failed
• Check for any signs of water intrusion while door panel is removed

Note: Window regulators are a common failure point on E46 models. Quality replacements can significantly improve long-term reliability.