Timing Chain Sprockets and Tensioner — Removal and Installation (BMW 3 Series E46)

Engine M43TU

Stars

1. Removing the sprockets is described in paragraph 7 as part of the chain removal procedure.

Tensioner

2. Set the engine to the TDC position of piston No.1 and secure the crankshaft as described in paragraph 3.

3. Remove the chain covers as described in paragraph 6.

4. Press the lower end of the tensioner shoe to loosen the chain and push the tensioner plunger down until the groove on the plunger aligns with the hole in the tensioner body. Lock the plunger in this position by inserting a rod or drill of the appropriate diameter into the hole and groove.

5. Unscrew the tensioner housing mounting bolts and remove it from the engine (Fig. 8.5).



6. Do not remove the tensioner rod until the tensioner is installed. Do not attempt to disassemble the tensioner - a special proprietary device is required for its assembly.

7. If a new tensioner is purchased, it is also locked in the depressed position. Do not pull out the lock until the tensioner is installed in place.

8. Installation is carried out in the reverse order of removal, taking into account the following notes.

• a) Check the condition of the sealing ring and replace it if necessary.
• b) Do not remove the retainer until the tensioner is in place.
• c) Install the chain covers as described in paragraph 6.

Engine N42

Stars

9. Removing the sprockets is described in paragraph 7 as part of the chain removal procedure.

Tensioner

10. The hydraulic chain tensioner acts on the right guide shoe. Unscrew the tensioner assembly (see fig. 7.29). Be prepared for oil to leak from the hole. The sealing ring will need to be replaced during assembly.

11. If the tensioner plunger needs to be replaced, hold the unit vertically with the hex head facing down. Push down on the plunger to squeeze all the oil out of the housing. Repeat the procedure if necessary.

12. Replace the sealing ring and screw the unit back into place. Tighten the plug to the required torque.