Explaining oil colour change  

What does it mean when my lubricant changes colour?

It’s normal to see oil colour change without experiencing any lubrication issues. There are several factors that can cause an oil to change colour after use including oxidation, deposits and contamination. Even just an increase in oil temperature may cause an additive to change colours, 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 colour 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 colour from clear to red or purple. This is normal behaviour for the product and does not adversely affect the performance of the lubricant or equipment.

Mobil engineers have found in numerous cases that an oil can change colour 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 Serv℠ Lubricant Analysis laboratory. The oil report will indicate if the lubricant is operating within normal parameters, based on colour and performance testing.