My truck broke down the other day, it ran out of fuel, well sort of, it was only taking fuel from the tank not connected to the fuel gauge and run it dry. As soon as it happened I knew what it was as it happen to me before with another Volvo.
With a bit of help from the HATO’s closing one lane of the M40, managed to get 20ltrs out other tank and got moving again.
Anybody had the same problem or knows why it happens?
muckles:
My truck broke down the other day, it ran out of fuel, well sort of, it was only taking fuel from the tank not connected to the fuel gauge and run it dry. As soon as it happened I knew what it was as it happen to me before with another Volvo.With a bit of help from the HATO’s closing one lane of the M40, managed to get 20ltrs out other tank and got moving again.
Anybody had the same problem or knows why it happens?
Check the breather and fuel cap on the non drawing tank. If no air can get in the vacuum effect stops fuel syphoning over. Also check/replace the cross over pipe and all it’s clamps etc. It could be getting air in it periodically and airlocking thus stopping the syphon effect. I had this on a Mk 1 years ago and on a Scania too 
FYI if it happens again take both caps off and shove a rag or some thing in the top of the full tank and an airline (Even the curly wurly duster type will do). That will usually get the flow started again and with the other tank being dry the pressure difference will maintain the flow 
Same as above, also when you are filling up, take both caps off and try to fill the non drawing one first if poss. If you replace the cross pipe, put shut off valves on both ends just in case. If you shut the valve before filling, you dont need to open both caps and you can run on one tank and keep the other full for emergencys where you struggle to find a place to fill up like cornwall.
what year is the truck the version 1 does not have a cross over pipe the 2 tanks are joined together on the cross member behind the gear box the 2 feeds and returns go together in a t piece the problem is usually the tank top breather in the sender unit or thr wrong caps i tend 2 use 2 vented caps its printed in the inside of the cap vented or non vented using vented allows them to breath easier keeping the fual leval equal in both tanks
Thanks for the information a few things to look at.
Both trucks it’s happened to me on are series 2 FH’s,
Both times it happened to me I’d only put fuel in one of the tanks, I know this time it was in the tank that stayed full, can’t remember what I did the last time as it was in 2009. But both times I didn’t remove the cap from the other tank.
Do you think this upsets the air pressure balance?