What Kind Of Engine Oil To Use - Chevrolet 2005 T-Series Owner's Manual

What Kind of Engine Oil to Use

Look for these two things:
•
CI-4 or CH-4
Oils designated as API CI-4 or CH-4 are
recommended for your vehicle. The CI-4 or CH-4
designations may appear either alone, together or
in combination with other API designations,
such as API CI-4/SL.
These letters show American Petroleum
Institute (API) levels of quality.
Notice: If you use oil that does not have this
designation, CH-4, you can cause engine damage
not covered by your warranty.
Notice: Use only engine oils that have one of these
designations CI-4 or CH-4 for the DURAMAX™ diesel
engine. Failure to use the recommended oils can
result in engine damage not covered by your
warranty.
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