Technical Doblo 1.6 Multijet - Can I tee into the fuel return pipe for a diesel heater?

[con95a]

If I tee into the fuel return line for a diesel heater, does anyone know if this will create problems or is it likely to work?

I want to install a Chinese diesel heater with it's fuel supply coming from the main diesel tank. I know it's possible to add a secondary fuel riser however I have a window cleaning tank bolted into the van which covers the fuel tank access hatch, so I big pain to remove. I don't like the idea of dropping the fuel tank either.

 

[bugsymike]

If I tee into the fuel return line for a diesel heater, does anyone know if this will create problems or is it likely to work?

I want to install a Chinese diesel heater with it's fuel supply coming from the main diesel tank. I know it's possible to add a secondary fuel riser however I have a window cleaning tank bolted into the van which covers the fuel tank access hatch, so I big pain to remove. I don't like the idea of dropping the fuel tank either.

I would have thought if you can get a T piece fitting on the return line at a join , but I would be very wary of disturbing the hard plastic fuel pipes as may be a problem sealing again.

 

[jackwhoo]

I would suggest no because it is likely the heater fuel pump would draw in air from the open tank end which is almost always above the fuel level.

 

[bugsymike]

I would suggest no because it is likely the heater fuel pump would draw in air from the open tank end which is almost always above the fuel level.

Good point I had forgotten.
Also if running heater with engine off there would be no flow anyway.

 

[con95a]

Good point I had forgotten.
Also if running heater with engine off there would be no flow anyway.

Ah that is something I wondered and would be a big problem, it would be used when the van is off 99% of the time...

In that case, anyone dropped the tank on this van? Is it difficult?

 

[bugsymike]

Ah that is something I wondered and would be a big problem, it would be used when the van is off 99% of the time...

In that case, anyone dropped the tank on this van? Is it difficult?

May be quicker to remove your water tank to get access.
I do recall a Fiat Ducato owner with a fuel leak where the camper conversion guys had drilled the tank and fitted a pipe for the diesel heater and I think he ended up having to buy a new fuel tank.
I know it sounds a logical solution to use the same tank, but given the small amount one of those heaters consume, would it be easier to fit a small plastic outboard motor fuel tank that could simply be topped up by opening the boot/tail gate.?

 

[Abarthmultijet]

On a 2011 1.3 Multijet we have the diesel heater (Webasto) on the return line for almost 14 years now. Works like a charm. For the test of the return line, we waited for the fuel gauge to be so empty that the needle would not move. Then sucked fuel out of the return line and got plenty of fuel out. (stopped after 5 Liters or so)

 

[bugsymike]

On a 2011 1.3 Multijet we have the diesel heater (Webasto) on the return line for almost 14 years now. Works like a charm. For the test of the return line, we waited for the fuel gauge to be so empty that the needle would not move. Then sucked fuel out of the return line and got plenty of fuel out. (stopped after 5 Liters or so)

Was that with ignition off and on/running, as OP wanted to do that I believe?
It would have been my first option, until @jackwhoo pointed out the chance of drawing air from the tank.

 

[Abarthmultijet]

Sucking fuel out of the tank was with the ignition off, but it works both ways.

 

[con95a]

On a 2011 1.3 Multijet we have the diesel heater (Webasto) on the return line for almost 14 years now. Works like a charm. For the test of the return line, we waited for the fuel gauge to be so empty that the needle would not move. Then sucked fuel out of the return line and got plenty of fuel out. (stopped after 5 Liters or so)

Hey thanks for sharing that, how did you T into the return fuel line?

 

[Abarthmultijet]

Not entirely sure, but I think it was cut, make sure there is no diesel left in the pipe and then heated with an heat gun with a heatshrink attachment. Then Pushed the T piece in. (see attachment) It is Webasto Part 9001344B

 

[Huzzy]

Not entirely sure, but I think it was cut, make sure there is no diesel left in the pipe and then heated with an heat gun with a heatshrink attachment. Then Pushed the T piece in. (see attachment) It is Webasto Part 9001344B

Why do you have to fully empty the pipe

 

[con95a]

In the end I bit the bullet and removed my window cleaning tank, and that was the hardest part. If you've got the access hatch above the fuel tank I think now it's easier and worthwhile to add a standpipe into the sender as the stock fuel lines are undisturbed (zero potential for causing problems to the engine) and I could always cap off the standpipe if it became obsolete.

 

[Abarthmultijet]

Why do you have to fully empty the pipe

Because else the pipe will not be pliable enough. The fuel inside the line will cool off the pipe too quickly