M1-Series Tanks… Protect Engine with Right Oil

Mechanics, you might get away with using any ol’ engine oil in your car, especially if it’s a clunker. But when it comes to an M1-series tank, the type of oil you use can mean the difference between a tank that runs like a Swiss watch or one that’s in the shop getting its very expensive AGT 1500 engine replaced.

The TMs and LOs are specific about what to use: MIL-PRF-23699. But keep in mind there are three different classes of oil under this specification, each with its own set of NSNs. The class of oil you use can either help or hurt the engine, depending on the situation.

The Classes

High Thermal Stability (HTS) Class. This class is for normal engine use. HTS class turbine oil contains special anti-coking additives that help prevent bearing and seal damage. That means more operating hours between major repairs and big-time cost savings.

Standard (STD) Class. This class should be used only as an emergency substitute if HTS oil is unavailable.

Corrosion Inhibiting (C/I) Class. This class is specially designed for long-term storage only. C/I class oil contains additives that make it foam-, wear- and corrosion-resistant. Use it in tanks that will be stored outdoors for longer than 6 months or indoors for longer than 12 months.

While in storage, you may need to exercise, move or perform maintenance on the tank. C/I oil is OK as long as usage doesn’t exceed 50 hours and the tank is going right back into storage.

When the tank is coming out of storage and back into regular operation, drain the C/I oil and replace it with HTS engine oil.

What to Order

Class Size NSN 9150-
HTS 8-oz 01-439-0764
HTS 1-qt 01-439-0756
HTS 55-gal 01-439-2070
STD 8-oz 01-476-1075
STD 1-qt 01476-1074
STD 55-gal 01-476-1083
C/I 8-oz 00-180-6266
C/I 1-qt 00-985-7099
C/I 55-gal 00-681-5999

The 2014 version of the TARDEC POL Products guide lists C/I class oil first on Page 7. Don’t be misled, though! HTS is the #1 choice for normal operations. If you’d like a copy of the guide, email PS at:



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