The switch between the internal combustion engine (ICE) and battery-powered motor challenges engine oil in several ways:
Switching between an electric motor and ICE causes hybrid engines to run cooler, leading to water and fuel build-up in the oil. This can disrupt some oils and cause engine deterioration.
Hybrids repeatedly switch between the electric motor and ICE. In some hybrids, the engine can also ramp up to high engine speeds quickly. Some oils can’t keep up, reducing engine performance and protection.
The ICE in a hybrid powertrain recharges the battery that powers the electric motor. Cooler running and lower oil temperature can lead to reduced engine efficiency and in turn, poorer fuel efficiency and charging of the battery.