Coolant contributes to a large percentage of all engine failures.
The presence of coolant (glycol) or water in an engine or transmission lubricant, indicates contamination from a number of possible sources. With coolant contributing to a large number of engine breakdowns, the failure to detect contamination can be extremely costly.
For example, bearing manufacturers have indicated that as little as 0.2% water contamination in oils can halve anti-friction bearing life.
Increased levels of sodium indicate the leakage of coolant inhibitor chemicals into the oil. The sodium is left behind in the oil even if the water evaporates.
| Causes | Effects |
| Low operating temperature | Equipment failure |
| Defective seals | High viscosity |
| New oil contamination | Poor lubrication |
| Coolant leaks | Corrosion |
| Improper storage | Increased operating temperatures |
| Cracked cylinder head | Acid formation |
| Weather -moisture | Reduced additive |
| Product of combustion | Harmful sludges and deposits |
| Recommendations |
| Check head bolt tension |
| Check head gaskets |
| Inspect heat exchangers and oil coolers |
| Check for correct operating temperatures, thermostat settings, etc |
| Evaluate equipment suitablility for applications |
| Avoid intermittent use if possible |
| Change oil and filters |
| Check for external moisture sources |
