🔍 Key Concepts

• Effect of fuel dilution on lube oil properties (viscosity, lubricating film, flash point) • What centrifuging, filtering, and settling actually remove from oil (e.g., water, solids, sludge) • When manufacturers/USCG guidance call for a complete oil change instead of treatment

💭 Think About

• Think about whether fuel is present as large droplets/contaminants or mixed throughout the oil—would a separator or filter catch it? • Ask yourself which process is designed mainly for solids and water removal versus one that deals with chemical/mixture contamination. • Consider the risk to bearings and cylinder walls if thinned oil stays in service—what is the safest corrective action?

✅ Before You Answer

• Verify what contaminants centrifuges are best at removing from oil. • Verify what filters can and cannot remove (particle size, type of contaminant). • Verify what you are instructed to do in practice when lube oil shows excessive fuel dilution in a lab report or manufacturer’s guidance.