Soot and other insolubles are a mixture of combustion residues and oxidation products. Soot consists mainly of the following combustion residues: ash, carbon and partially oxidized fuel, a small amount of oil oxidation products and spent lubricant additive.

Soot in engine oil is:

Carbon from incomplete combustion and to a small extent from lubricants
Organic polymers from the oxidation of lubricants or fuels
sulphates, from the combustion of sulfur from the fuel and from the reaction with BN additives
Asphaltenes (predominant in engines running heavy oil) - a very dirty crankcase is known as "black paint" and is associated with asphaltenes in the oil

High levels of soot and other insolubles cause:

Increased oil viscosity
Bearing and tread wear
Clogging of oil lines and filters
Contamination in the area of ​​the piston rings, piston ring grooves and the piston crown

Testing equipment for carbon black and other insolubles

Electronic Insolubles Test Meter - A stand-alone test device with modern measurement technology that provides fast results with very good repeatability.

Insolubles Test Papers - Test strips that provide qualitative results by comparison with comparison charts.