HT Lubricant Services Include:


Used Oil Analysis

Used Oil Analysis programs for engine oils, such as Petro-Canada's "LUBRI-TEST" provide several customer benefits:

  • Reduce unscheduled vehicle downtime
  • Improve vehicle reliability
  • Help organize effective maintenance schedules
  • Extend engine life
  • Optimize oil change intervals
  • 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:

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

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

  • 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 @ 40C and cSt @ 100C
  • 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.
  • Water - presence due to condensation from low temperature engine operation or from a leak in the cooling system.
  • Dilution - the amount of gasoline or diesel present in an oil.
  • Insolubles - suspended material present in the oil, due to presence of soot from diesel fuel combustion and contamination from airborne dust, dirt or sand.
  • 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.
  • Total Base Number - measures the reserve alkalinity of an oil, which is the ability of an alkali to neutralize the effect of acid formation.
  • 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.


Used Oil Analysis Tests

Contaminant Warning Levels

Test Warning Limit

cSt @ 40C

25% change versus the new oil viscosity

cSt @ 100C

15% change versus the new oil viscosity
Coolant Any positive identification
Water Greater than 0.1%
Dilution Greater than 5%
Insolubles 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

Element Warning Limits Comments
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.