2001 V70 Missing Gas Tank

Beirut · Post by **Beirut** » 18 May 2014, 06:30

Okay, not missing. But half of it is. Kind of. Whenever I fill up with gas it won't fill more than half a tank. It gets to the point where it automatically shuts off the nozzle and there's no more room in the tank. I can even do it by hand, topping it off, and the gas is definitely up to the point where there's automatic shut-off.

I then start the Volvo and the gauge shows 1/2 tank.

Any ideas? Thanks.

Post by **abscate** » 18 May 2014, 17:20

So the filler neck is full of gas, but the tanks shows 1/2 full on the gauge?

How far can you drive until it shows empty, or stops?

Beirut · Post by **Beirut** » 19 May 2014, 16:58

1st question, yes.
2nd question, something in the 220 mile range.

Post by **abscate** » 20 May 2014, 04:59

Does the tank look normal underneath, not pushed up or dented in?

It sounds like there is only room for 10 gallons or so. That's a puzzler.

Is it an XC by any chance, with a saddle tank?

benrk · Post by **benrk** » 20 May 2014, 12:27

Habe you ever tried to drive it til it stops for being out of fuel?

Beirut · Post by **Beirut** » 20 May 2014, 17:52

Yes, it's an XC, though I don't know about a saddle tank. It came without an owner's manual and I've only looked at the online version of the owner's manual a few times. Are you saying there are two separate tanks, and some kind of switch that one switches between them?

Post by **abscate** » 23 May 2014, 04:42

Enlightenment bursts upon us like the sun.

On XC, because of the drivetrain hardware, the fuel tank straddles the drivetrain and is in fact two chambers of roughly (you guessed it) 9 gallons each.

The fuel pump pulls from one of these but also pumps gas from one side to the other.

Search for a diagram using saddle tank search term.

There are no prizes for figuring out this has something to do with your project.

benrk · Post by **benrk** » 23 May 2014, 10:00

This tank think is puzzling me the whole time, I'm used to having trouble with the two tanks on the truck on cold winter days, the return flow splitters are prone to freeze up & block the syphon line between the tanks, but there is only one sending unit for the gauge on the tank that feeds the engine supply, so the gauge will show full & empty, it just goes down twice as fast as you're only feeding from 1 tank.

Do these Volvos have 2 sending units, one in each half & the control module extrapolates the shown volume?
I'm inclined to think the swimmer on the sending unit is stuck & only goes halfway up, but then you should still get the full range & just drive with the gauge showing half for the 1st half of the tank.

Taking a jug of fuel along & driving til it stops would help figuring out wether it's a physical problem or just a wako gauge.

Post by **jimmy57** » 23 May 2014, 11:35

There are two sending units.
If one of them is hung at bottom them the tank reads 1/2 at most.
Reading fuel tank level sensors in REM on that year model will tell you which one is reporting empty.
I have seen the float break and the metal arm will fall to bottom and also the float could be hung because the sender is twisted and the float can't rise without binding on side of tank.