Article by: Paul Axford
Applies to: all models with the M30 big six engine (this article was written with a 730i).
A vibration felt through the steering while starting the car was my cue that the engine mounts had failed.
The replacement procedure involves raising the engine about 5 cm (2″) one side at a time and replacing each mount.
You will need a 17mm socket and about 45 cm (18″) of extensions to reach the top fasteners after removing the air cleaner assembly.
The lower fasteners are easily reached with a short extension after removing the underside engine valence. Be sure to remove the two “push to lock” fasteners at the upper corners of the fan shroud to allow the fan additional upward movement.
This job took me only an hour to complete, and that was outside in the rain. Before you start I recommend in advance attempting to loosen the mount fasteners from above to ensure you do not need additional tools.
The car front end will need to be placed on jack stands or ramps to allow a trolley jack to clear the engine sump. Be careful when jacking under the car.
I use the stock jacking points since they happen to fit the jack’s nose perfectly. The inboard gussets under the front floor pan that many people use are more fragile than they look – be careful.
The cross member under the engine seems to be fine however, and is a good location for the jack stands.
To lift the engine on the right side I used a block of wood jammed under the right-side engine mounting arm and lifted that with the trolley jack. Watch your fingers while changing out the mount in case something slips.
For the left side I used a flat block of wood under the sump. Needless to say, wipe clean the mount contact surfaces before inserting the new mounts and note there is a locating key to lock the mount’s position in rotation.
Tighten fasteners appropriately for a 10mm fastener – meaning “not much.”
Pics are of the right and left mounts, respectively, before replacement.