Petro Gulf Analysis Program

PetroGulf Oil Analysis programs for engine oils, provide several customer benefits:

  • 1. Reduce unscheduled vehicle downtime
  • 2. Improve vehicle reliability
  • 3. Help organize effective maintenance schedules
  • 4. Extend engine life
  • 5. Optimize oil change intervals
  • 6. Reduce cost of vehicle maintenance

Used engine oil analyses are carried out principally to determine the overall condition of an oil. Monitoring an oil's condition at successive intervals, over a relatively long time period, can be used to establish:

  • 1. Presence of Undesirable Contaminants, such as:
    • > Excess Wear Metals
    • > Gasoline or Diesel Fuel
    • > Coolant
    • > Road Salt
    • > Dirt, Sand or Dust
  • 2. Optimum Oil Change Interval

The following items are tested to determine the condition of an engine oil :

  • 1. Viscosity - is the measure of an oil's resistance to flow. An oil can "thicken-up" due to oxidation, the presence of contaminants, or evaporation of light components. It can "thin-down" due to oil shearing or fuel dilution. Reported as cSt @ 40°C and cSt @ 100°C
  • 2. Coolant - ethylene glycol is the major component of antifreeze coolant sytems, so the presence of glycol is determined. A positive test result indicates a defective gasket or a cracked head/block. Detection of glycol requires immediate attention, as it reacts quickly in a hot engine to form varnish and sludge.
  • 3. Water - presence due to condensation from low temperature engine operation or from a leak in the cooling system.
  • 5. Insolubles - suspended material present in the oil, due to presence of soot from diesel fuel combustion and contamination from airborne dust, dirt or sand.
  • 6. Total Acid Number - expresses the quantity of base required to neutralize all the acidic constituents present in the oil. Often an indicator of how oxidized an oil has become.
  • 7. Total Base Number - measures the reserve alkalinity of oil, which is the ability of an alkali to neutralize the effect of acid formation.
  • 8. Wear or Additive Metals - The presence of the following elements is usually looked for by Inductively Coupled Plasma Emission Spectroscopy: Aluminum, Barium, Boron, Calcium, Chromium, Copper, Iron, Magnesium, Phosphorus, Sodium, Tin and Zinc.

Oil Analysis Tests

Contaminant Warning Levels


Warning Limit



cSt @ 40°C

25% change versus the new oil viscosity

cSt @ 100°C

15% change versus the new oil viscosity


Any positive identification


Greater than 0.1%


Greater than 5%


0.5% or more

Total Acid Number

More than 5.0 units

Total Base Number

No lower than 3.0 to 4.0 units

Wear Metals Warning Levels


Warning Limits


Iron (Fe)

Greater than 100 ppm

High levels indicate worn crankshafts, valves, cylinder-liners, bearings

Chromium (Cr)

Greater than 10 ppm

High levels indicate worn piston rings, bearings or contamination by antifreeze

Copper (Cu)

Greater than 20 ppm

High levels indicate worn bearings and bushings

Tin (Sn)

Greater than 10 ppm

High levels indicate worn bearings and bushings

Aluminum (Al)

Greater than 20 ppm (>80 ppm Aluminum Block Engines)

High levels indicate worn pistons or engine block

Lead (Pb)

Greater than 25 ppm

High levels indicate worn bearings. Where leaded gasoline used, results are meaningless

Boron (B)

Greater than 20 ppm

High levels indicate anti-freeze leak. Some engine oils contain a boron dispersant additive. Check sample of new oil

Silicon (Si)

Greater than 20 ppm

High levels indicate presence of dust or sand. May also be due to high level of silicone anti-foam. Check sample of new oil

Magnesium (Mg), Calcium (Ca),
Barium (Ba), Sodium (Na),
Phosphorus (P), Zinc (Zn)

These elements may be part of the additive package. They remain in the oil and do not deplete.