Fuel & Solvent dilution of lubricants by either unburned fuel or lubricant degradation reduces the lubricant's effectiveness.  The thinning of the lubricant can lead to decreased lube film strength adding to the risk of abnormal wear.  Depending on certain variables, when fuel dilution of crankcase oil exceeds 2.5 to 5%, corrective action should be taken.  Fuel & Solvent dilution is measured by gas chromatography or FT-IR.  The results are reported in percent volume.

 Fuel/Solvent Dilution CAUSE

• Incorrect air to fuel ratio
• Extended idling
• Stop and go driving
• Defective injectors
• Leaking fuel pump/lines
• Incomplete combustion
• Incorrect timing

 Fuel/Solvent Dilution EFFECT

• Metal to metal contact
• Poor lubrication; Oil thinning
• Increased overall wear
• Cylinder ring wear
• Decreased additive effectiveness
• Risk of fire or explosion
• Reduced MPG
• Decreased oil pressure
• Reduced engine performance
• High operating cost
• Shortened engine life

 Fuel/Solvent Dilution SOLUTION

• Check fuel lines, worn rings, leaking injectors/seals, pumps
• Analyze driving/operating conditions
• Check timing
• Avoid prolonged idling
• Change oil and filters
• Evaluate equipment vs. design
• Check fuel quality

Repair/replace worn parts.