BY and large, low-temperature sludge is still one of the most prevalent types of engine deposit. It is formed wherever conditions are such that oil contaminants may settle out.
A recent large survey shows that control of sludge is influenced by many factors, such as engine design, accessory equipment, oil quality, and operational judgment.
Poor quality oil, due to its instability, forms sludge very rapidly.
The use of h-d oils is recommended, but h-d oil should not be charged into a dirty engine.
The greatest measure of control, however, can be obtained by observing the ordinary rules of good engine maintenance, proper operating conditions, hot crankcase drains, and servicing of filters and other accessories.