By now, you’re probably already using PC-11 or are about to. To date, ExxonMobil has accumulated more than 27-million miles of testing on its CK-4 and FA-4 PC11 diesel engine oil blends. The main thing fleet owners need to remember is there are two sub-categories, CK-4 and FA-4:

CK-4 – replaces CJ-4 oils, is a higher-viscosity blend with the high-temp, high-shear qualities needed for older-style diesel engines and is back-serviceable.

FA-4 – In order to meet increasing emissions and fuel efficiency standards, new diesel engine designs will benefit from using a lower viscosity engine oil. FA-4 does not have the same high-temp, high-shear qualities as CK-4 and is not back-serviceable.

Know Your Fleet

Fleet owners and managers should understand the needs of their fleet as well as OEM recommendations surrounding the engine oils required for operation.

CK-4 – use in fleets with older equipment, typically pre-2013

FA-4 – use in fleets operating newer, EPA 2017 equipment (follow OEM recommendations)

CK-4/FA-4 – mixed fleets may need to use both blends

Standardizing engines across fleets is best, but budgeting for in-house oil storage where both PC-11 blends are required is the best option for multi-use fleets.

How To Prepare

It is important to have your fleet’s maintenance department prepared for use of PC-11 diesel engine oils. Some recommendations include:

• Clean storage tanks before switching to new oils. If tanks can’t be fully-drained, reduce current capacity to 10-percent or less before filling with PC-11

• A hot drain is recommended when switching an engine from CJ-4 to either CK-4 or FA4

• Ongoing used oil analysis to monitor engine oil performance

• Continue to follow OEM recommended oil change intervals

Moving Forward

PC-11 will not change the best practices that have made many fleets successful. If anything, it should allow fleets to perform with better efficiency and fuel economy while allowing for a more data-driven approach to drain intervals and vehicle performance.