If traces of oil leakage through the camshaft seal are found, first check if the crankcase ventilation system is clogged and if the hoses of this system are pinched, repair if necessary
If the oil leak continues, replace the oil seal.
You will need - all the tools necessary to remove the timing belt (see "Replacing the timing belt and the Renault Logan engine roller"), as well as a "16" wrench, a screwdriver, pliers, a hammer.
Disconnect the wire from the negative terminal of the battery.
Remove the timing belt.
The belt does not need to be removed completely, it is enough to remove it only from the camshaft toothed pulley.
Loosen the camshaft pulley bolt, holding the pulley from turning, as shown in the photo, with the handles of the pliers inserted into the pulley holes and a wrench or a large screwdriver
Remove the bolt from the camshaft hole.
Remove the pulley from the camshaft shank.
Using a screwdriver, remove the oil seal from the cylinder head seat.
Before installing a new oil seal, inspect its sealing lip.
It should be smooth, without tears, dents and rubber influxes.
The stuffing box spring must be intact and unstretched.
Lubricate the working lip with engine oil.
To make it easier to press the gland, make a small chamfer on its seating edge using a needle file or a fine emery wheel.
Install the oil seal with the working lip inside the block head socket, carefully fill the working lip onto the camshaft (for example, using a wooden stick) and press it in with a suitable mandrel to the stop.
You can use a suitable size head from the tool kit or an old oil seal as a mandrel
Install all removed parts and assemblies in the reverse order of removal
Install the camshaft pulley with the protruding part of the hub towards the engine.
The tightening torque of the camshaft pulley bolt is 45 Nm (4.5 kgf-m).
Adjust the tension of the timing belt and accessory drive belt.