I have PL-M oil, which I bought for firearm use. It is surplus. I used it on a firearm and left it for 2 to 3 months. When I picked it up, I noticed all the controls were stiff. I took the firearm apart and noticed the oil became sticky and hard. In some places, it had become a sort of shell. Is that normal? This occurred at room temperature. It is pretty old (probably from the 80s) and I'm not sure if I should send it back. Below is a description:
From the "US Archive":
1.1.6 MIL-L-3150B(2): Lubricating OH, Preservative, Medium (Military Symbol
PL-M (NATO Code: 0-192)
General characteristics : Preservative lubricating oil consisting of a petroleum
fraction containing additives necessary to meet specification requirements.
Uses : Intended for lubrication and protection against corrosion of ferrous and
nonferrous metals, interior of gear assemblies, transmissions, differentials, etc. Not
intended for the protection of internal combustion engines.
From the "US Archive":
1.1.6 MIL-L-3150B(2): Lubricating OH, Preservative, Medium (Military Symbol
PL-M (NATO Code: 0-192)
General characteristics : Preservative lubricating oil consisting of a petroleum
fraction containing additives necessary to meet specification requirements.
Uses : Intended for lubrication and protection against corrosion of ferrous and
nonferrous metals, interior of gear assemblies, transmissions, differentials, etc. Not
intended for the protection of internal combustion engines.