Explaining oil color change

What does it mean when my lubricant changes color?

It’s normal to see oil color change without experiencing any lubrication issues. There are several factors that can cause an oil to change color after use including oxidation, deposits and contamination. Even just an increase in oil temperature may cause an additive to change colors, or initiate oil oxidation, darkening the oil.

For instance, Mobil Velocite™ Oil No. 3 is a very light viscosity oil and could – depending on the system condition and the oil used in the system previously – act like a mild solvent, solubilizing material that may have been deposited inside the system piping. As a result, there may be a color change but it does not affect the lubricant performance.

Similarly, Mobil Rarus™ SHC 1020 series products have an antioxidant package that, when activated, can change the lubricant color from clear to red or purple. This is normal behavior for the product and does not adversely affect the performance of the lubricant or equipment.

ExxonMobil engineers have found in numerous cases that an oil can change color and yet have no impact on its performance. However, to make sure there is not a problem with the lubricant, you can contact a Mobil™ distributor to send an oil sample to our Mobil Lubricant Analysis laboratory. The oil report will indicate if the lubricant is operating within normal parameters, based on color and performance testing.