Engine Sludge build up: The Black Death of sad engines!

Image from: www.tunemytoyota.com

Engine sludge build up used to be better (Or more sensationally) known as “Black Death”; probably accurately describing the appearance an effect it has on an engine, if not rectified in time.

Basically what happens is the oil oxidises and becomes contaminated to the point where it thickens to form a sludge and changes colour. The high viscosity, in turn, leads to the oil pump not being able to pick up this sludge from the oil pan; causing oil starvation.

What causes engine sludge build up?