Mercedes GL450 GL550 Spark Plug Replacement 2007-2012
A Mercedes GL450 requires spark plug replacement every 60K miles, in this DIY article I will show you how to replace the spark plugs.
1. Remove the cross brace.
2. Disconnect the air ducts to the air filter housing and remove them out of the car.
3. Disconnect the air pump hose from the air box.
4. Unclip the air box from the air mass sensor. There is a metal clip that you need to push back towards the firewall.
5. Remove the air box.
6. Disconnect the ignition coil harness.
7. Remove the two screws that hold the coil to the valve cover.
8. Gently pull the coil out of the cylinder head.
9. Remove the old spark plug and discard.
10. Install the new spark plugs and torque them 23Nm.