Aren't many of the tanks run by gas turbines? Obviously the lubrication requirements there are different than in the diesel and petrol-fired vehicles.
I think I read somewhere that for the diesel/petrol, they run a 15W-40, bought from the lowest bidder, by the drum or tanker-load. But anything with a turbine would obviously get a more appropriate oil.
i was informed by someone at a mobil shop that the US government has contracts with mobil. LOL of course this is the same people that looked at my "dark oil" which was amsoil and had 13K miles on it that since it was dark it meant that I had sludge and that I need to use their engine flush. oh well just throwing that out there. mobil of course could be the lowest bidder to our government for all I know??
In the early 90's the M-113 that I drove used Mobil 15W-40. Had a big detroit deisel engine in it. I know that we used Mobil 15W-40 because when we changed the oil, the 55 gal drum was clearly labeled. Side note, we sampled the oil every so often and were instructed to change the oil only after the results of the oil analysis were in....
k1xv has the answer....
The military puts out a Mil Spec and company's bid on the amount needed. I have hauled many truck loads of 55 gallon oil. The barrels are painted green and have the Mil Spec and weight of the oil and that's it. From memory way back then, the Wt. was straight 30. But that was 20 years ago. I picked up the barrels at a no-name refinery in Long Beach California and brought them to Orange County Military Hub in Seal Beach.Aaaah, then picked up some in-ert (no-contents) bombs and brought them to Coronado Island in San Diego.....Memories!
Last time I looked (about 3 years ago) they were using safety-kleen recycled 15w-40 in the fleet vehicles at the base I was at.
and don't forget, all 4 branches drive and maintain humvees, not just the Army.
Last time I asked a Marine, they range from Citgo,Shell,Chevron..(The Navy also use them too)
Come to think of it, my aquintances 1995 Civilian Hummer recommend Shell Rotella... so i would think the military use the recommended oil.
I don't know about HMMWVs, but I can tell you that the Coast Guard stations around here use Delvac 1 in the 47' Motor Life Boat Detroit Diesel engines. Whenever I am in their boat house, I am tempted to "borrow" a couple of gallons from one of the drums!
Last I heard from some Tankers Mobil was the oil used in the Gas Turbines in the M-1's. Heard all gas vehicles used refined motor oil - Old used filtered oil with good additives dumped back in the mix.
MILSPECs are designed around the applications and operating conditions. I vaguely recall from my "Motor-T" days that there was one spec for normal-to-hot conditions and another for very cold. Since my unit was in Florida, we didn't worry much about which spec to apply, as to oil anyway. At the user level, the mech puts in whatever gets shipped over from the warehouse. It's up to the folks who run the supply chain to determine which suppliers will be awarded contracts to provide the military anything -- oils, bandaids, ammo, flu vaccine, whatever.