Checking the condition and replacing the power unit supports (BMW 5 Series E28)

Powertrain mounts rarely require attention; broken or worn mounts should be replaced immediately, otherwise the additional loads on the transmission line components that arise in this case will lead to their intensive wear and failure.

Checking the status

1. During the inspection, the power unit should be slightly raised to remove its weight from the supports.

2. Jack up the vehicle and support it securely on its axle stands, then slide the jack under the oil pan. Place a large block of wood between the jack head and the pan, then carefully lift the engine with the jack just enough to take its weight off the jack stands.

DO NOT place any part of your body under an engine supported only by a jack!

3. Check the rubber parts of the mounts for cracks, hardening or separation from the metal components.

4. Sometimes the rubber part splits right down the center.



5. Check whether the support brackets and the elements of the power unit and the car body move relative to each other (use a large screwdriver or crowbar as a lever for this purpose). If movement occurs, lower the engine and tighten the mounting bolts or nuts.



6. To reduce wear, apply a special rubber preservative to the supports.



7. On models with the M40 engine, check the condition of the dampers on each support by removing them and trying to compress and stretch them.

8. If the damper offers only very little resistance, it should be replaced.

Replacement

1. If you have to replace the dampers on the M40 engine, simply loosen the bolts, then install the new dampers and tighten the bolts.

2. To replace the mounts, disconnect the negative battery cable, then jack up the vehicle and support it securely on the axle stands if you have not already done so.

If your vehicle's radio is equipped with an anti-theft system, make sure you enter the correct code before disconnecting the battery.

If the instrument cluster displays the wrong language after connecting the battery, refer to Section Anti-theft audio system and instrument cluster language, which describes the procedure for installing the required language.

3. Support the power unit as described in point 2.



4. Loosen the large nut securing the bracket to the support (indicated by the arrow).



5. Raise the engine slightly, then loosen the lower nuts/bolts securing the mount to the subframe and remove the mount.

6. Install the support in the reverse order of removal. For greater reliability of tightening the nuts/bolts of the supports, apply a special thread sealant to them.