12 13 Carrying out engine cleaning (N54, N54T, N53, N43)
WARNING: This page is about a different car, the 2010 BMW 135i, 2009 BMW 135i, and 2008 BMW 135i. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT:
When cleaning the engine, it is absolutely essential to keep the ignition coil covers fitted in order to protect the injectors.