Note: The upper drive chain cover can be removed separately. If you need to sleep both covers, you will need special tools.
Withdrawal
Disconnect the ground wire from the battery.
If you are removing the lower drive chain cover (top cover can be removed separately), remove the fan, fan shroud, heatsink, and fan drive belt pulley.
On engines where the distributor cap is mounted directly on the timing chain cover, remove the distributor cap, slider and the black plastic cover underneath.
On early M30 engines, remove the distributor from the top drive cover.
Remove the valve cover.
If it is necessary to remove the lower drive chain cover, remove the crankshaft pulley from the vibration damper/hub. Holding the pulley stationary with a wrench (install center bolt), unscrew the pulley bolts with another wrench.
Remove the hub/damper by blocking the crankshaft with the special tool and loosening the large central bolt.
If the special tool mentioned in the previous paragraph is not available, on some engines it is possible to block the crankshaft by removing the flywheel/drive plate inspection cover and inserting a wide screwdriver into the ring teeth.
Unscrew the plug and remove the drive chain tensioner spring. If the tensioner plunger did not come out with the spring, remove it from the mounting hole.
Caution: When unscrewing the tensioner cap, hold it securely as it may be pushed out by the spring.
If you are removing the top actuator cover on the engine, remove the thermostat cover and remove the thermostat.
To remove the lower drive cover on this engine, loosen the alternator mounting bolts and move the alternator aside. Remove the front lower mounting bracket bolt and loosen the other bolts. Also disconnect the power steering pump bracket and move it to the side.
Remove the bolts and nuts securing the upper drive chain cover to the engine block and remove the cover. Sketch the location of the bolts so that you can install them in the same holes from which they were removed. Remove the top drive chain cover. If the cover does not come off, tap it lightly with a rubber mallet. On engines of early years of release, remove the distributor drive shaft.
Remove the bolts and nuts securing the lower drive chain cover to the engine block. Don't forget to remove the three bolts that secure the base of the cover to the front edge of the oil pan. Loosen the remaining pan bolts.
Run a sharp knife between the oil pan gasket and the lower drive chain cover. Be very careful not to damage or stain the gasket so that it can be reused.
Separate the bottom cover of the drive chain by tapping on it with a rubber mallet or by inserting a wooden wedge under it and hitting it with a hammer. Do not pry the cover with a screwdriver as this may damage the contact surfaces.
Using a scraper, remove all traces of old sealant from the cover and engine block.
Caution: Be very careful not to scratch the soft aluminum surfaces. Also take care not to damage or contaminate the pan gasket. After all traces of sealant have been removed, wipe the surfaces with a rag soaked in the solution.
Installation
Replace front seals. Apply a small amount of oil to the sealing lips of the oil seals.
Apply a thin layer of special sealant to the oil pan gasket where it contacts the lower drive chain cover. Apply additional sealant to the edges of the gasket adjacent to the engine block,
Caution: If the oil sump gasket is damaged, instead of installing a new gasket, you can cut off the damaged front part, and using this as a template, cut out part of the new crankcase gasket. Cover the exposed interior of the crankcase with a rag, then clean off any traces of old sealant from the area where the gasket was removed. Attach the cut piece of the new gasket to the oil sump with a special adhesive, then apply the sealant as described at the beginning of this section.
Coat both sides of the new timing chain lower cover gasket with sealant, then attach the cover to the front of the engine. Install the bolts and tighten them to the required torque. Work in a diagonal sequence.
Attention: First tighten the bolts securing the cover to the engine block, then the bolts securing the oil sump to the cover. If the gasket protrudes, cut it off.
Install the top drive chain cover in the same way as the bottom cover. If the gasket protrudes, cut it off with a blade.
Attention: After applying the sealant, the assembly must be completed within 10 minutes, as after this time, the sealant will harden.
Start the bolts (1) And (2), then tighten the remaining bolts in the sequence shown, and only then finally tighten the bolts (1) And (2).
Install in reverse order of removal.