Major differences

Fuel economy

engine close up

As CK-4 engine oils get closer to arriving you may hear the term High Temperature High Shear (HTHS) viscosity. CK-4 oils are being referred to in the industry as “High HTHS” engine oils.

Shear stability

vehicle light close up

Shear stability is the ability of the oil molecules to resist shearing under severe stress inside the engine. Oil shearing results in a lower viscosity, and excessive viscosity loss could impact the ability of the oil to protect vital engine parts. The new CK-4 standards call for improvements in shear stability versus CJ-4 oils. New, more stringent shear stability test limits are being developed to validate that each oil’s shear stability meets the new guidelines.

Oxidation stability

numbered test tubes

Oxidation is one of the primary causes of oil breakdown and is accelerated by higher operating temperatures. The next generation of engines are being designed to run hotter. So, CK-4 standards call for improved oxidation stability versus CJ-4 oils.

Aeration control

bubbling lab flask

The new CK-4 standards call for improvements in aeration control. Aeration is when the engine oil starts to develop tiny air bubbles, foam or both, which can impede the oil’s ability to protect the engine. To monitor the effectiveness of the new oils, they will have to pass a new aeration test called the Caterpillar Engine Oil Aeration test.

Senior male researcher carrying out scientific research in a lab

Why do we need a new oil standard?

Oil technology and engine technology go hand in hand. Changing regulatory limits challenge engine manufacturers to reduce emissions. As engine manufacturers begin to create a new generation of cleaner, more fuel-efficient diesel engines, they need a new generation of higher-performing diesel engine oils to protect them. And they need to know those oils will be available throughout the country to every diesel engine owner.

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