I would like to hear from a real mechanic about my truck.

Ok so here's the story. I ran out of fuel one day and learned my truck was only getting fuel from one tank. After a day and a half at the ship, my company decided that I should run on one tank and they routed me down to Phoenix so their "mechanics" would fix my truck. After I got my truck back and did my 34. I started the day with a little over half a tank. Over the course of 2 hours or so, my fuel gauge went back to full. On a hunch I stopped and sure enough, my passenger side was almost empty and my driver side full. So I brought the truck back to the yard and reported it to the mechanic and he says "oh, the tanks are designed to drain fuel only one at a time. When the first runs out, it will switch to the second one." I am no mechanic, but that sounds stupidly wrong. Is he full of #### or is that how it workd

 

No new truck works that way. But what type of truck?

 

Sounds like tank vent is plugged.

 

You are correct to be suspicious. Dual draw , dual return tanks should remain at or about the same level during operation and should be equally level while stopped. Vents being plugged is the easiest and simplest to check. From there kinked or restricted suction or return lines can also cause the same issue. Can be a bugger to find at times. If you crack the fill caps loose and run it and it stays level you indeed have a plugged vent on the driver side. If it doesnt level out while setting you have blocked lines between tanks.

Year, make and model? Guessing you only have the one sending unit for gauge and on the driver side?

 

It's a 2017 freightliner cascadia. I was guessing the fuel gauge was set to the driver side.