Color is not an indicator of oil quality or suitability

Color will vary between oils, and it is not an indicator of oil quality or suitability. An oil’s color should not be judged by light reflected from a sample; instead, the sample should be tilted to allow the color of light transmitted through a film of the oil to be assessed.

Some oil discoloration is normal in engine use of gas turbine oils.

• The extent of discoloration will vary with the oil in use and the severity of the engine.
• Excessive discoloration can indicate engine problems or contamination.
• Black oil is not an oil problem; it arises due to specific engine conditions.

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