Fuel tank return line

Forum Home > OKA Maintenance > Fuel tank return line

OKA4WD.com
Administrator
Posts: 412
From Tony Lee:

... To the bottom of the tank or not?

Three pipes into the fuel tank(s); rear one is breather, centre is suction line and front one is excess fuel return line.
Anyone know whether the fuel return line goes right to the bottom of the tank or just into the top.
thanks
Tony
May 23, 2010 at 12:50 PM Flag Quote & Reply

OKA4WD.com
Administrator
Posts: 412
From Peter_n_Margaret:

Why does it matter?
Peter
OKA196
May 23, 2010 at 12:51 PM Flag Quote & Reply

OKA4WD.com
Administrator
Posts: 412
From Tony Lee:

Very difficult to suck fuel out of the top of a container.
I could of course use the proper suction line to get the diesel to fill the auxiliary tank supplying the Webastos but would prefer not to alter that because it is much more critical.
The return line doesn't matter so much.
Tony
May 23, 2010 at 12:52 PM Flag Quote & Reply

OKA4WD.com
Administrator
Posts: 412
From Peter_N_Margaret:

Sorry Tony, I thought your question was about the return line.
Why not just "T" off the main line for the Webasto and not have an auxilary tank at all?
Cheers,
Peter
May 23, 2010 at 12:53 PM Flag Quote & Reply

OKA4WD.com
Administrator
Posts: 412
From Tony Lee:

Yes, was abvout the return line, but there lots of ways to do it.
The heater uses more that half a litre per hour on full power so on a long trip the fuel used calculations could be seriously messed up. Hence the separate tank so usage (car and heater) can be more easily monitored.
As for taking the fuel from the supply line - this introduces possibility of leaks from at least 4 extra joints and since they are in the suction line are difficult to find and can cause major problems with losing prime to the fuel pump.
Taking the fuel from the main tank direct to the heater means potentially crappy fuel being used for the heater, so a filter will be needed anyway. The diesel cooktop is apparently more susceptible to dirty fuel problems so it is worth taking a bit of extra care.
Taking the feed from the return line doesn't cause that sort of problem but of course is only possible if it goes to the bottom of the tank - which is the case in some fuel systems. If it does go to the bottom then there is little chance of anything external to the engine causing problems with the engine fuel system.
Obviously not difficult to find the answer, but I prefer not to start disassembling a system that is in perfect working order if there is a chance that someone knows the answer. When I receive the workshop manuals, that may give the answer. Using a mirror through the filler neck didn't work because the tank baffle gets in the way.
May 23, 2010 at 12:54 PM Flag Quote & Reply

OKA4WD.com
Administrator
Posts: 412
From Peter_n_Margaret:

NOW I understand.....
No idea what the answer is though..........
Cheers,
Peter
OKA196
May 23, 2010 at 12:55 PM Flag Quote & Reply

OKA4WD.com
Administrator
Posts: 412
From Joe Baz:

I disconnected the return fuel line and blew into it, and can't hear any bubbles, so the line doesn't reach the bottom of the tank.
May 23, 2010 at 2:32 PM Flag Quote & Reply

OKA4WD.com
Administrator
Posts: 412
From Tony Lee:

Thanks Joe, that will save me the indignity of getting a mouth full of dust doing the same.
May 23, 2010 at 2:33 PM