Engine front and rear seals and oil pan gaskets aren't as easy to change as the average valve-cover gasket. Timing cover gaskets and seals are also more-challenging.

This allows oil to leak from the timing cover and if the oil leak is left neglected, road dirt and grime attracts to oil-covered areas and sticks.

What fits what: The scoop on mixing and matching small-block Ford water standard- and reverse-rotation pumps and front timing covers.