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Interpreting Oil Analysis


Indicator Acceptable Levels Engine Problem What to Check
Silicon (Si) and 10 to 30 ppm Dirt ingestion Air intake system, oil filter plugging, oil filler cap and breather, valve covers, oil supply
Aluminum (Al)     Blower, camshaft intermediate bearings, turbo bearings, crankshaft thrust bearings.
Iron (Fe) 100 to 200 ppm Wear of cylinder liner, valve and gear train, oil pump, rust in system Excessive oil consumption, abnormal engine noise,performance problems, oil pressure, abnormal operating temperatures, stuck/broken piston rings
Chromium (CR) 10 to 30 ppm Piston ring wear Excessive oil blow-by and oil consumption, oil degradation
Copper (CU) 10 to 50 ppm Bearings and bushings wear, oil cooler passivating, radiator corrosion Coolant in engine oil, abnormal noise when operating at near stall speed
Lead (Pb)* 40 to 100 ppm Bearing corrosion Extended oil change intervals
Copper (CU) and 10 to 50 ppm Bearing lining wear Oil pressure, abnormal engine noise, dirt being ingested in air intake, fuel dilution, extended oil drain intervals
Lead (Pb)* 10 to 50 ppm    
Aluminum (Al) 10 to 30 ppm Piston and piston thrust bearing wear Blow-by gases, oil consumption, power loss, abnormal engine noise
Silver and 2 to 5 ppm Wear of bearings Excessive oil consumption, abnormal engine noise, loss in oil pressure
Tin 10 to 30 ppm    
Viscosity Change   Lack of lubrication Fuel dilution, blow-by gases, oil oxidation, carburetor choke, ignition timing, injectors, injector pump, oil pressure
Water/Anti-freeze   Coolant leak or condensation Coolant supply, gasket sealed, hose connection, oil filler cap and breather
Possible Sources of Elements in Used Oils
Aluminum (Al) Blower, camshaft intermediate bearings, turbo bearings, crankshaft thrust bearings.
Barium (Ba) Detergent additive, grease additive.
Boron (B) Coolant additive, grease additive, EP additive (limited).
Calcium (Ca) Hard water; detergent additive, oxidation inhibitor; road salt.
Chlorine (Cl) Antiwear additive, EP additive.
Chromium (Cr) Piston ring tace surface, coolant additive. May be found on some pump component surfaces.
Copper (Cu) Slipper (wrist pin) bushings, connecting rod and crankshaft main bearing, cam follower roller bushings, rocker arm clevis pin bushings, connecting rod bushings, camshaft thrust washers, anti-corrosion additive (limited), copper-kote sealant. (Cu + Zn Brass. Cu + Sn = Bronze)
Iron (Fe) Grey iron cylinder liners, malleable iron pistons, hardened steel camshafts, crankshafts, gears.
Cast iron induction-hardened rocker arms, valve bridges, alloyed steel cam follower rollers, etc.
Lead (Pb) Overlay on bearing surfaces, grease additive. Gasoline additive, EP additive, antiwear additive, detergent additive. (Limited use due to environmental concerns.)
Magnesium (Mg) A constituent in some aluminum alloys, detergent additive, possible indication of "hard" water.
Manganese (Mn) Detergent additive, unleaded gas additive.
Molybdenum (Mo) Friction modifier, surface coating on some piston rings, anti-wear additive.
Nickel (Ni) Bearing overlay, turbo charger blades, crude oil constituent, stainless steel components.
Phosphorus (P) Antiwear additive, EP additive.
Potassium (K) Coolant additive.
Silicon (Si) Antifoam additive, dirt/dust, grease additive, coolant leak, gasket sealant.
Silver (Ag) Bearings, solder.
Sodium (Na) Road salt, coolant additive, detergent additive (limited), grease additive.
Sulphur (S) Antiwear additive, EP additive, detergent additive.
Tin (Sn) Overlay of some connecting rod and crank bearings. Surface coating on some components such as pistons.
Vanadium (V) Surface coatings, turbine impeller blades, valves.
Zinc (Zn) Antiwear additive, oxidation inhibitor, corrosion inhibitor.



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