Crankshaft seals — replacement (BMW 3 Series E46)

Front crankshaft oil seal

Engine M43TU

1. Replacement of the cuff is described in paragraph 6 as part of the lower timing chain cover removal procedure.

Engine N42

2. Remove the pulley with the damper from the crankshaft nose (see paragraph 5). Do not remove the hub.

3. Mark the depth of the seal installation in the cover. On the engines we had to have a depot with, the seal was installed flush with the outer plane of the cover.

4. Remove the old cuff with some kind of hook. Alternatively, drill a couple of holes in the cuff, screw screws into them and pull the screws out with pliers together with the cuff (Fig. 18.4). Lubricate the drill with grease so that all the chips stick to it. Be careful not to damage the pulley hub or the working surfaces of the block and crankshaft under the cuff. If these methods fail to remove the cuff, remove the pulley hub and cut the cuff with a chisel.



5. Wipe the pulley hub and the surface under the seal in the housing. Lubricate the hub surface with engine oil.

6. The new seal is supplied with a mounting mandrel. Insert the new seal into the mandrel and place the mandrel on the hub.



7. Align the two horizontal grooves on the side surfaces of the cuff with the parting plane of the engine crankcase (fig. 18.7,3). Then press the cuff to the previous depth using a piece of pipe that rests only on the outer, hard part of the cuff (fig. 18.7,6).





8. Using the tools included in the BMW seal replacement kit, coat the seal grooves with the primer included in the kit.

9. Using the syringe included in the kit, fill both grooves with sealing compound (Fig. 18.9). Cover the ends of the grooves with primer.



10. Install the pulley with damper on the crankshaft as described in paragraph 5.

Rear crankshaft oil seal

Engine M43TU

11. Perform the actions specified in paragraph 14 of Chapter 2B.

Engine N43

12. Remove the flywheel as described in paragraph 19.

13. Measure and record the cuff installation depth.

14. Drill a couple of holes in the cuff, screw in the screws and pull out the screws with pliers together with the cuff (see fig. 18.4).

15. Wipe the surfaces of the crankshaft and housing under the seal. Lubricate the surface of the crankshaft under the seal with engine oil.

16. The new seal is supplied with a mounting mandrel. Insert the new seal into the mandrel and place the mandrel on the nose of the crankshaft.

17. Align the two horizontal grooves on the side surfaces of the cuff with the parting plane of the engine crankcase (see fig. 18.7.a). Press the cuff to its previous depth using a piece of pipe that rests only on the outer, hard part of the cuff (see fig. 18.7,6).

18. Using the tools included in the BMW seal replacement kit, coat the seal grooves with the primer included in the kit.

19. Using the syringe included in the kit, fill both grooves with sealing compound (see fig. 18.9). Cover the ends of the grooves with primer.

20 Install the flywheel as described in paragraph 19.