Short answer
EOS-4.5 is Mack Trucks’ engine oil standard for its heavy-duty diesel engines, introduced in the same API CK-4 era as Volvo’s VDS-4.5. Mack presents it as a step beyond API CJ-4 and its earlier EO-O Premium Plus standard. Mack approves specific oils to EOS-4.5, and many products list it together with older Mack approvals.
Mack’s oil standard lineage
Mack has long issued its own engine oil standards, with names such as EO-N, EO-O Premium Plus and EOS-4.5. Each was introduced as emissions hardware and API categories changed.
EO-O Premium Plus was the CJ-4-era standard. EOS-4.5 arrived with CK-4 and became the standard Mack promotes for its current engines.
What EOS-4.5 covers
EOS-4.5 applies to Mack MP-series engines such as the MP7 and MP8, which share Volvo Group engine engineering. That is why EOS-4.5 and VDS-4.5 appeared together and are often listed on the same products.
Like other engine maker standards, EOS-4.5 adds Mack and Volvo Group testing to the API CK-4 baseline, and it is tied to Mack’s drain interval guidance.
Older approvals still on labels
Many current oils list both EOS-4.5 and EO-O Premium Plus. The older approval remains relevant for older Mack engines whose manuals name it.
For a mixed fleet of older and newer Mack trucks, an oil carrying both approvals can cover both, provided the viscosity grade suits each engine.
Checking the requirement
Use the Mack operator’s manual or Mack service information for the engine’s required standard and grade. Then confirm “Mack EOS-4.5” on the oil’s current data or label.
A CK-4 claim alone does not confirm Mack approval, so look for the Mack standard by name.
Frequently asked questions
Is Mack EOS-4.5 the same as Volvo VDS-4.5?
They are separate approvals from the same engine family background and are often held by the same products, but each is listed separately.
Does EOS-4.5 replace EO-O Premium Plus?
EOS-4.5 is the newer standard. Older engines may still list EO-O Premium Plus, and many oils carry both.
General maintenance information. Always follow your vehicle or equipment manufacturer’s requirements and the current product data. Questions? Email [email protected].