We replace the front crankshaft oil seal when traces of oil appear on the surfaces of the oil pump cover and the engine oil pan under the auxiliary drive pulley.
For clarity, we show the operations on the dismantled engine.
Removing the timing belt (see Checking the condition and replacing the timing belt).
Remove the timing pulley from the toe of the crankshaft.
Pry off the oil seal with a screwdriver...... and remove it from the oil pump housing.
We apply a thin layer of engine oil to the working edge of the new oil seal and put the oil seal on the crankshaft neck.
We press the oil seal into the socket of the oil pump housing until it stops using a tool head or a piece of pipe of a suitable size.
We assemble in the reverse order.