Do Bypass Filters Hurt Oil Analysis Results?

"Regarding bypass filters that heat the oil to 200°F, do they remove water and or glycol from the oil? Wouldn't this prevent oil analysis from being able to detect water or glycol?"

Because the heater is designed to vaporize low boiling point volatiles such as water and fuel, these contaminants would not show up in the oil analysis in their original concentration. While this could make it difficult to detect or assess the severity of leaks and abnormal ingress of fuel and water, it is still probably much better to vaporize them from the oil as soon as possible.

The same is true for soot and dirt. High soot levels can be an indication of many problems such as air cleaner restriction, high blowby, and general combustion efficiency problems. Removing the soot to achieve contamination control is better than leaving it in the crankcase so that oil analysis can detect it in an unaltered state.

Regarding glycol, 200°F is not hot enough to vaporize ethylene glycol. However, such temperatures can contribute to glycol being converted to glycolic acid, formic acid, sludge and varnish. Normal engine operating temperature will usually do the same thing. Therefore, you typically don't test for glycol in the lab but rather the elemental additive residuals that ingress with glycol into the crankcase oil (Na, K, Si, B, etc.).

"How does soot get into my oil?"

The primary cause of soot is improper combustion. When clean fuel burns completely (which is a form of oxidation), the only by-products are water and carbon dioxide. However, due to impurities and inefficiencies in the combustion cycle of an engine, numerous other by-products are produced, including SOX, NOX, soot, acid and other transition products. Soot is highly polar, carbon rich particles. Several factors influence poor combustion, including:

• Rich mixture
• Lugging
• Excessive idling
• Cool jacket temperatures
• Poor atomization of fuel
• etc.

Most soot and other by-products of combustion exit through the engine's exhaust system. A percentage, however, blows by the rings from the combustion chamber into the crankcase, where it contaminates the lubricant. Soot can have the following effects on the engine and lubricant:

• Increased lubricant viscosity
• Blocked oil flow passageways, causing starvation
• Decreased effectiveness of antiwear, dispersant and detergent additives
• Increased wear

In an appropriate effort to reduce pollution, the EPA has placed new restrictions on emissions, which is forcing the use of exhaust gas recirculation (EGR) starting next year, which essentially gives soot and other combustion byproducts a multipass opportunity to blow by the rings into the crankcase. In the near future, the stakes for soot management will increase dramatically. Oil analysis and lubrication management practices must be adjusted to deal with the increased threat caused by soot contamination.