Fuel dilution in oil can cause serious engine damage. High levels of fuel (>2%) in a lubricant can result in decreased viscosity, oil degradation, loss of dispersancy, and loss of oxidation stability. Fuel dilution is one of the most important lubricant failure modes in internal combustion engines. It usually occurs due to improper fuel-to-air ratio. Fuel dilution can also occur due to excessive idling, piston ring wear, or defective injectors and loose connectors.
Measurement Techniques