Fuel Dilution

Feb 5, 2014 | condition monitoring, fuel analysis, oil analysis

Have you ever had an Oil Analysis Report come back stating there is Fuel in your Oil? This is bad news, fuel can have major effects on the oil and do extraordinary damage.

So how did it get there? Fuel dilution occurs when unburnt fuel accumulates in the engine crankcase. This may have been caused by excessive idling, engine lugging, defective fuel injectors or incorrect spray patterns, dribbling injectors, incorrect or restricted fuel and air, overcooled engine operation, worn piston rings or liners, incorrect choke settings or even frequent short drives. There are many causes why fuel turns up in oil.

What effects will this have on my Engine?

  • Increased internal wear by causing viscosity loss
  • Increased wear by diluting the anti-wear additives
  • increased corrosion by introduced organic and sulfuric acids
  • Potential fire or explosion risk when high levels of dilution occur

How much is Bad? All fuel dilution is bad, as mentioned above, fuel dilution indicates there is a combustion problem and it will have an effect on your engine. Some laboratories will allow Caution or Monitor limits to be set at 2% providing that viscosity, wear, additives and soot values are all  within guidelines. Here at Techenomics we prefer to set our caution limit at 1%, we want you to be aware that it is not normal and the issue needs to be looked at before it becomes a bigger problem that could lead to catastrophic effects.


If you are experiencing problems with your oil, please contact us for further assistance

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