Is there any reg or rule of thumb on the painting of fuel tank caps on military vehicles? Red= gas. Yellow= Diesel.
You are correct. Red is mogas - gasoline. Yellow is diesel.
Check your references, though. The colors are sort of generic and universal, but the actual practice is not universal nor even consistent over periods of time.
For instance, this was very common in the US Army in the late '60s, '70s and even into the mid-'80s, but now just about everything in the US Army runs on diesel, so it’s pretty rare to see after the introduction of the Humvee.
Soviet / Russian AFV “plumbing” in engine compartments often color-codes the various hard lines (yellow for fuel, green for water, brown for oil, blue for compressed and natural pressure air, red for fire suppression). However, even this is not 100% universal and even on the same vehicles only some of the lines might be color-coded.
References for what ifs are scarce. Aiming for Third World / 1990s. From what Igather there is a pissing contest in the civilian world over yellow vs green for diesel … caps, jerry cans, fuel pumps. (at BP youre screwwed, all the nozzles are green.)
I presume that you are referring to fuel cans and not to the cap on the vehicle itself. On vehicles the caps usually match the surrounding area paint or may be a bare metal under an armored latched cover.
In the US Army, it was usually the top of the can above the weld seam painted red to denote MOGAS (gasoline). This was done since most vehicles took diesel fuel and most cans carried diesel. The red was so you could tell the few cans that carried MOGAS, usually for generators.
was asking about the caps that go on the big tanks IN the vehicle. I know most are the same as the exterior but I’ve seen ones painter (usually red) denoting fuel type (or maybe so some half trained conscript can find it or doesnt pour oil in) Jerry cans I’m planning on yellow caps and a band around the can.
I have never seen any fuel tank cap painted any color other than the vehicle color (wheeled vehicles w/external caps) or bare metal (armored vehicles with armored covers over the cap).
For the jerry cans, it depended on the time. Jerry can tops were painted yellow for diesel in the '70s and '80s when some vehicles still used MOGAS. I have not seen any yellow painted jerry cans since the late '80s to early '90s. By them most MOGAS vehicles were gone and you might have some MOGAS cans for the generators. If a can was not painted red, it was diesel inside.
That’s not a US Army thing to have fuel caps color coded. It would not be effective at night anyways, because then refueling is usually done under blackout conditions, with at best red lens flashlight. And again SOP is that tactical refueling is done from tanker vehicles or fuel bladders. Most of the time you go the fuel… sometimes it comes to you. Oil for lubing various items in the vehicle is kept in Jerry cans. And then poured into an oil can to refill those oil needing items such as the final drives, differential, transmission, etc. It’s usually not possible to get those 5 gallon Jerry cans into the compartment to lube those items.
As far as the conscript goes, we’ll that’s why there are NCOs to monitor the soldier, to watch out for and head off the screw ups.
Unless it’s the NCO that screws up! One time in Germany had a dumb-ass SFC pour 30wt oil into the gas tank on the generator for my M577. Really made a mess of things!
DOH!!! SFC Homer Simpson?