Over time, during operation, the gasket under the engine head cover loses its elasticity and strength and oil leaks from under the cover

You can try tightening the cover bolts.

If the oil leak from under the cylinder head cover could not be eliminated by tightening the cover bolts, replace its gasket.

You will need: a 12 wrench, a screwdriver.

Disconnect the wire from the negative terminal of the battery.

Drain the cooling system.

Replacing the cylinder head cover gasket ZMZ 406Replacing the cylinder head cover gasket ZMZ 406

Loosen the inlet hose clamp and move it aside.

Disconnect the hose and wire harness holders.

Replacing the cylinder head cover gasket ZMZ 406Replacing the cylinder head cover gasket ZMZ 406

Remove the crankshaft position sensor harness from the holder.

Remove the high voltage wire ends from the spark plugs.

Note. If the replacement of high-voltage wires is not expected, the tips can not be removed from the wells of the cover

Replacing the cylinder head cover gasket ZMZ 406Replacing the cylinder head cover gasket ZMZ 406

Loosen the ventilation hose clamp and remove the hose

Loosen the suction hose clamp and remove the hose.

Replacing the cylinder head cover gasket ZMZ 406Replacing the cylinder head cover gasket ZMZ 406

Disconnect the wire blocks from the primary connectors of the ignition coil

Remove the bolts securing the head cover and remove the cover along with the gasket, high-voltage wires and ignition coils.

Replacing the cylinder head cover gasket ZMZ 406

If you removed the cylinder head cover, then you need to flush the oil deflector from deposits

Removing the ZMZ-406 cylinder head cover and flushing the oil deflectorRemoving the ZMZ-406 cylinder head cover and flushing the oil deflector

Remove the cover gasket.

Remove the gaskets for sealing the candle channels.

Removing the ZMZ-406 cylinder head cover and flushing the oil deflectorRemoving the ZMZ-406 cylinder head cover and flushing the oil deflector

We unscrew six screws with a screwdriver and, prying with the same screwdriver, remove the oil deflector.

After washing all the parts in kerosene, wipe dry.

We degrease the mating surfaces of the oil deflector and valve covers, as well as the screws.

Removing the ZMZ-406 cylinder head cover and flushing the oil deflector

We apply glue-sealant to the oil deflector and, after setting it in place, press it tightly.

Assemble all the parts in reverse order.

We install a new gasket on the cover and connect all the hoses and wires.

new

After disassembling, thoroughly rinse all gearbox parts in kerosene, blow with compressed air and inspect

Possible pump malfunctions may include: leakage of the diaphragm and valves, decreased elasticity or breakage of the diaphragm spring, wear of pump drive parts