PC-11…Are You Ready For This?
by Michael D. Holloway, CLS, OMA I
National Sales Manager, Tribology

It seems like only a few years ago the American Petroleum Institute (API) service category for heavy-duty diesel motor oil C-J4 engine oil specification was launched. Actually, it was over 10 years ago. Prior to the implementation there was a combination of enthusiasm and skepticism. Some thought that the new specification would provide lower pollutants with a reduction in sulfonated ash and lower zinc phosphorus compounds as not to poison the new emissions system, while others thought that engine wear would increase dramatically due to the reduced zinc phosphorus compounds that have been used for decades as anti-wear agents. It has been argued that both occurred. Whether you were for it or against you had no choice but to comply. Engine oil blenders, engine and component manufacturers developed products to meet the government requirement. The time is drawing near when a new specification for engine oil shall be introduced. It is in the ‘Proposed Category” with engine makers and oil formulators. For now it is referred to as PC-11. The API will apply a new name upon approval. This new requirement is considered the most drastic to date.

The requirements put forth by the API are based on federal requirements to lower emissions (Green House Gas Reduction) and increase fuel efficiency. The most significant aspect of this new category is in viscosity. Normally the factory fill requirements for diesel engine oil are SAE 15W-40 with a few exceptions calling out for SAE 10W-30. The viscosity is classified according to kinematic viscosity analysis. The new category would use a different test method and actually be a grade thinner; SAE 5W-30. The reasoning is based on establishing less resistance to flow within the engine while maintaining film strength to continue to afford protection. A thinner oil has been shown to achieve this yet in order for it to continue to provide performance, various ingredients have to be used to provide functionality. The old method of qualifying the viscosity (the kinematic method) cannot be used. The new method – High Temperature High Shear rheometry has to be used. Another challenge for oil formulators is to make the new blend backward compatible with CJ-4 oil and maintain engine durability.

While this may seem very confusing for the end user, consider oil blenders and the engine builders. They will have to consider several more requirements such as new oil performance to include new oxidation, ring wear, piston scuffing, oil aeration, and viscosity increase requirements. This shall be no easy task yet fortunately preliminary work suggest that the goal to create an engine oil for improved wear protection, improved emissions and fuel economy is well within reach. The new category is expected to go into effect in 2016.