TANK, FUEL

550 671 31A TANK, FUEL is the main reservoir for the rig's diesel fuel, plain and simple. It's not just a big can; it's designed to hold a decent volume to keep the engine running for a good shift, sometimes longer, without needing a top-up. You'll usually find internal baffles in there to stop the fuel from sloshing around too much when the rig's moving or drilling on uneven ground, which helps prevent fuel starvation to the engine's pickup tube. It's the critical link between your fuel delivery truck and the engine actually making power.

When this tank starts giving you trouble, it's usually pretty obvious. The most common thing we see is a leak, either from a crack, a bad weld, or corrosion, especially if the rig's been working in salty or damp conditions. You'll definitely smell diesel, and then you'll spot the drips or a wet patch under the rig. Less common, but still a pain, is internal contamination or a failing fuel sender unit. If the sender goes bad, your fuel gauge will be lying to you, which can lead to unexpected shutdowns. A really bad internal blockage or a collapsed pickup tube can also starve the engine, making it sputter or cut out even with a full tank.

Replacing one of these isn't rocket science, but it's a job you want to do right. Always drain the old tank completely first – safety first, right? When you're putting the new one in, take a good look at all the fuel lines, especially the return and supply lines, and the vent line. Make sure none of them are kinked or cracked, and check the mounting straps for any signs of fatigue. A common oversight is forgetting to properly clean out any debris from the old lines or not checking the new tank's internal filter screen, if it has one, before hooking everything up. You don't want to introduce new problems right after fixing an old one.