Pump Jack

With the recent conversion to diesel and the current yields, 38 diesel is the maximum you can use without overfilling the output (2280 crude / 5 stacks, 6460 LGF / 13 stacks).
Compared to the previous effective yield (after subtracting the value of wood for refining) of ~2.91x, the new effective yield is ~1.15x, which works out to a 12.8x nerf in yield (ouch). But if you have a full load of diesel, you'll still make a tidy profit (about 1.7k LGF or 5.66 diesel profit from a load of 38). As long as nobody ever steals any of it...
Frankly, I think the new yields are a total deal-breaker for pump jacks on PVP servers. It's just not worth the risk for a measly 15% profit. I don't know what FP were thinking.

This thing is present at:
Trainyard Water Treat Power plant
it effectively triples your low grade fuel once you refine the crude oil pumped from it if you have the time to d oso.

Takes way too long. Just go barrel mining and get alot more

It can be pretty good if you are willing to leave it on and be away from it. I like to stick some fuel in and then go do other stuff, hit up a couple of monuments then come past on the way back.