Fuel tanks not equalizing and left tank empties faster than right one

Are the tanks same capacity? If they are not then one will empty faster than other

 

Sounds like some kind of fuel blockage in either your tanks or fuel lines.

 

The return tee should be a valve designed to equalize the flow back. They can and do fail, especially on a truck of that age, so they divert more fuel to one tank than the other. The valve is sensitive to the backpressure caused by the level of fuel, so if there is a cracked return tube it can cause more fuel to go to that tank as well.

 

Mine does the same as the ops truck, though mine is the right tank that empties first. It has been this way the 6 yrs I have owned it. Never could find a plugged vent or collapsed fuel line. Tanks are clean & original. Is there a way to test the valve or do you just have to replace it?

 

I had a '99 Volvo that would do this. It turned out there was some debris stuck in they fuel pickup in that tank. One tank would empty out, you'd run out of fuel, the other tank with the debris would stay full, and sometimes even overflow from the returned fuel.

 

Often times the right tank will be a little higher than the left due to running in the right lane, crown of the road causes the right side to be lower in elevation than the left. This should not account for more than an inch or two difference though.

 

3/8!!! that's insane. I would have thoroughly investigated that before anything.