Fuel tanks

Doesn't matter which you fill first. Whatever floats your boat. The fuel system will automatically siphon from one tank to the other if you only fill up one. For example, if you fill just one from 1/2 to full, and the other tank is still 1/2 full, the fuel will equalize in the tanks and show 3/4 full on your gauge. It's not instant, it takes a bit of time.

The fuel gauge will do that on hills and curves. There are no baffles in the tanks and the fuel sloshes around and moves the sender. Some trucks don't move so much because of some delay built into the system to avoid the wild gauge swings. My Pete fuel gauge stays pretty steady.

 

What he said! These tanks have a line running between them and they run from each other, so when you fill both then your gauge is exact but if both tanks are empty then you fill one tank then your gauge will show 1/2 full when it evens out. Thanks.

 

And as i learned if one tank gats punctured you can cap off the bad one siphon the fuel to the good one and run off one tank but it sucks on a long heAvy run

 

One other thing on fuel gauges...my Volvo was an old...very old...Swift truck with 75 on the drivers side and 125 on the passenger. I have a theory that they tried to idiot proof their trucks by setting the sensor or whatever to still have 50 gallons when it reads empty. My computer read "0 MILES UNTIL EMPTY", the gauge was below the "E", and I could only cram 147 gallons in to the top, almost overflowing the tanks! I was fueling WAY too often until I figured that out, which I did VERY CAREFULLY!! I was in that truck long enough where I got a good feel for when I actually needed to fuel, and never ran out. Thought about trying to get it set more accurately, never bothered.

 

There is "equalizer" fitted on tot of tranny and when engine runs fuel level in tanks is equal, no matter what tank was full, what not, level goes equal. Some drivers put valves to select tank manually. BTW - not good idea to have assimetrical tanks. I used to work with Volvos (Belgium made cabovers) with different tanks. Sometimes one goes empty and engine sucks fuel with air and stalls. So I'd prefere two tanks of the same size