What additive keeps engines clean by preventing contaminates and deposits from collecting on surfaces? a. friction modifiers b. dispersants c. detergents d. anti-oxidants

Answer is: Dispersants

Explanation:

Dispersants keep contaminants (e.g. soot) suspended in the oil to prevent them from coagulating. Anti-foam agents inhibit the production of air bubbles and foam in the oil which can cause a loss of lubrication, pitting, and corrosion where entrained air and combustion gases contact metal surfaces.

So that's why the answer is: Dispersants

b. Dispersants

Explanation:

  Dispersants contribute in a very similar way to the dispersion of the various ingredients (also contributing to the homogenization of a compound), the lubrication of the molecular chains and, in general, the lubrication of all mixing ingredients, thus decreasing the temperature rise of the compound by reducing the heat developed by internal friction.