To access the glow plugs, you will need to:
1. Remove the engine cover.
2. Disconnect the electrical connector for each glow plug.
3. Use a 6-point 10mm socket to loosen the glow plug.
4. Remove the glow plug by hand.
Be careful not to drop the glow plugs into the engine. If you do, you will need to retrieve them with a magnet.
To install the new glow plugs, simply reverse the steps above. Be sure to tighten the glow plugs to the specified torque (25 Nm).