Lube Oil Analysis – Water + Antifreeze (Glycol) contamination e.g. through coolant leaks in engine oil


Water – Water content found in the system. This may be a freshwater source e.g. tap water, or saline water (with sodium), or coolant (with sodium and/or potassium and possibly glycol / antifreeze). In water based fluids, the water content needs to be within certain concentrations to maintain fire-resistance properties. If water is a contaminant in the system then it needs to be prevented from entering or removed after ingress (see Section on symptoms and corrective actions for details on how).

Glycol – this is an analysis linked to the water content. Glycol contamination suggests a coolant leak, incorrect sampling or use of a dirty top-up can.

Common Causes of Water/Glycol/AntifreezePotential ResultPotential Advice
  • Low temperature.
  • Poor seals
  • IBC contamination / improper storage.
  • Coolant leak
  • Leaking solenoid valve on purifier
  • Condensation / humidity
  • Exposed/free breathing tanks/header tanks
  • Leak of gland (Sterntubes)
  • Poor lubrication
  • Rust
  • Engine failure
  • Pressure check cooling system.
  • Check lube & coolant levels for any change.
  • Check if coolant or lube top-up increasing.
  • Check for source of contamination ingress.
  • Inspect oil cooler – submit coolant sample.
  • Check head gasket and tighten bolts if needed.
  • Check engine temperature not too cold causing moisture from combustion to condense.