Phillips 66® Guardol XT Full Synthetic Diesel Engine Oil is a premium quality,
full-synthetic engine oil developed for use in 4-stroke cycle diesel engines
operating under extreme temperature conditions. It meets API CK-4 performance
requirements for use in modern low-emission engines designed to meet 2007 and
later EPA on-highway exhaust emissions standards, and is backward serviceable
for use in older diesel engines. It is specially formulated for compatibility with
exhaust aftertreatment systems using diesel particulate filters (DPF), diesel
oxidation catalysts (DOC) and/or selective catalytic reduction (SCR). The fullsynthetic formulation provides excellent low-temperature properties for better
performance in harsh winter climates.
Guardol XT is formulated with synthetic base stocks and an advanced lowSAPS additive package to provide outstanding wear protection, soot control
and bearing corrosion protection in both conventional and EGR-equipped diesel
engines. It has excellent soot dispersancy to protect against abrasive wear and
soot-induced oil thickening, and to ensure good low-temperature pumpability
even with highly soot-laden oil. The full-synthetic formulation provides enhanced
oxidation resistance and thermal stability at high temperatures and improved lowtemperature properties compared with a conventional, non-synthetic formulation.