So you’re going to be doing oil analysis to keep your engines healthy. It will help extend their lives, for sure, or at the very least help you establish proper drain intervals. But what are the various terms that will be used to describe the state of your engine lube, and what do they mean? Read on…

CONTAMINATION
Silica usually means dust/dirt is being ingested into engine.

Potassium, sodium, glycol-coolant components-imply a coolant leak, often through the head gasket.

Diesel fuel indicates an injector or return-line problem.

Water can come from a faulty crankcase ventilation system, damaged head, block, coolant jacket, oil cooler, heat exchanger, etc.

Soot/sulphation/nitration are by-products of combustion; high levels may indicate blow-by, overloaded operations, a too-rich fuel-air mixture, excessive idling, etc.

WEAR METALS
Aluminum can come from wear to pistons, bearings, blower/turbocharger, pump vanes, thrust washers/bearings, oil-pump bushings, housings, etc.

Silver comes from wrist pin bushings, anti-friction bearings, silver solder.

Chromium comes from rings, some roller-taper bearings, liners, exhaust valves, coolant, rods, spools, gears, anti-friction bearings.

Copper from bearings, thrust washers, bushings, oil coolers, oil additives, cam bushings, valve-train bushings, governor, oil pump, etc.

Iron from cylinders, crankshafts, valve-train, piston pins, clutch, some pistons, rings, gears, bearings, liners, shafts, camshafts, pumps, cylinder bores, rods, etc.

Other metals such as nickel (alloy from gear plating, valve guides and ring lands, shafts, anti-friction bearings), lead (bearings, oil additives), and tin (bearings, piston plating, bushings).

ADDITIVE CONDITION
The additive-package condition is mainly indicated by the viscosity level and oxidation level. Presence in ppm of the nine elements noted in the main article is more valuable for confirming that the proper oil is being used than for assessing the state of the additive suite.