If an oil leak through the oil pan gasket cannot be eliminated by tightening its fastening bolts, it means that the gasket is severely deformed and must be replaced.
Perform work on a lift or a viewing hole.
You will need wrenches for 12,14,17 (sockets), extension, universal joints.
Remove the engine mudguard.
Drain the oil.
Unscrew the nuts of the two bolts securing the clutch housing to the booster and remove the bolts.
Remove two bolts securing the clutch booster to the cylinder block on both sides ...
Remove the clutch booster.
Remove the oil cooler drain hose nut and disconnect the hose from the oil pan fitting.
Remove the eleven bolts and four nuts securing the oil sump to the cylinder block and remove the engine oil sump
Remove the gasket from the cylinder block studs
Before installing a new gasket, degrease the pressure surface of the oil sump and cylinder block, then install the gasket in place.
Install the oil sump and tighten the bolts and nuts securing to the cylinder block evenly in a criss-cross pattern as shown
Install the removed parts in the reverse order of removal.
Fill engine oil.