Lubricating Oil, Internal Combustion Engine, Preservative Break-in

General Description

MIL-L-21260E is a preservative oil designed to provide long term protection of metal surfaces. This performance specification covers engine oils suitable for preservation, break-in, and lubrication of reciprocating internal combustion engines of both spark-ignition and compression-ignition types, and of power transmission fluid applications in equipment used in combat/tactical service.

Available in grades as noted below.


MIL-L-21260E is used as provided for internal metal protection. MIL-L-21260E can also be used for external metal protection by dipping the parts to be protected in a vat or spraying the parts to be protected with air sprayers, pump type sprayers or by pouring the product over the parts. Removal of protective films is accomplished by using a steam cleaner or washing the parts in mineral spirits.

Physical Properties

Appearance Dark Brown Liquid
Odor Mild Solvent Odor
Specific Gravity 0.90 - .098
Flash Point (minimum) 300º F
Melting Point Liquid as Provided

MIL-L-21260E meets following specifications:

Viscosity Grade Military Symbol NATO Code
SAE 10W PE-10 C-640
SAE 30 PE-30 C-642
SAE 40 PE-40 ----
SAE 15W-40 PE-15/40 ----


MIL-L-21260E is available in UN approved 5 gallon pail, 55 gallon drums and bulk quantities.


Observe warning label on containers. Normal precautions for industrial chemicals apply.

pdf MIL-L-21260E-PB (26 KB)

pdf MIL-PRF-21260E GRADE 10 SDS (190 KB)

pdf MIL-PRF-21260E GRADE 15W 40 SDS (188 KB)

pdf MIL-PRF-21260E GRADE 30 SDS (188 KB)