Engine Oils
Background & Properties
castrol.com/GPS
800 255 4417
May 2025
GPS
Industry Specifications
e "Radial" Polymer
Long chain polymers, which are efficient viscosity modifiers, are easily susceptible to shear breakdown due to
their long chain structure. Castrol's viscosity modifiers are radial in structure and are commonly termed
"radial" polymers. eir unique, compact shape makes them very resistant to breakdown and produces
engine oils with high VIs and excellent shear stability.
e best test for shear stability and viscosity is to measure the characteristics of an engine oil aer it has been
in service. A maintenance manager who monitors OEM recommended service intervals and understands the
operating conditions of his equipment can fully appreciate the economics and benefits of outstanding
viscosity performance.
Castrol's
Radial Polymers
Conventional
Normal
Sheared
A25
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