Fuel line T in Diesel heater

Hi all,
I am sure someone in the colder climates has installed a diesel heater and plumbed it into the van diesel lines ? Which line and where did you tee it in ? Looking at the lines coming out of the tank. Any help would be great. Thanks again

I think the slightly fatter line is the feed line.

Hi GPW yes that is correct, I will try the return line and see if that works.

I think the return also dips into the tank, so that's also a good option.
I tapped into my tank line, but cannot recall which one i choose!!
I'm not sure when I'll be able to look next, sorry!

Also, for 'engine fuel feed reliability' reasons, the return line is safer, as the fuel pickup is generally pure suction, so if the mod introduces an air leak the engine will struggle.

Hi.

As part of the 'refresh' (when will it ever end) I've got the fuel tank off my van for a number of reasons (might put up seperate post). While poking around inside the tank I've come to realise just how complex and cleverly-arranged it is. Thankfully the inside is really clean and tidy, which surprised me.

The relevant point here is to show the fuel pick up and return in the tank (well on mine anyhow).

Yes, the thicker pipe is the delivery and the thinner is the return. For a heater, I don't know whether it's best to T into the delivery or the return and yes the return is quite deep into the fuel well inside the tank. The depth of the tank at this point is close to 250mm and the filter basket sits at or very close to the tank's floor (the bottom of the basket is flattened and I think it sits on the tank's floor). This means it's possible to run the van with very little fuel in the tank.

The return pipe does not have a filter (why whould it?) and yes the end of the vertical return pipe is very close to the bottom of the tank. if your tank is not clean then the danger might be that you'll be picking up this crud. This might be one way of getting the dirt out of the tank, but I'm not sure this would be good for a heater.

I'm looking to fit a heater and will probably use the main fuel tank rather than a seperate one (probably) but an undeceided which line to choose and whether to fit additional valve(s) for isolation or add an in-line filter (especially if I use the return).

I think I might also explore whether there's space in the gray-water tank locker (RHS and accessible from outside) for a samll tank.

More questions than answers at this stage, but I hope the image is useful.

Cheers

Great post LH119V,
I ended up teeing into the return line of my fuel system for my diesel heater and it has been working great and without issue all Australian winter. I have got a fuel filter inline also.

I am about to put a diesel heater in my van as well and was planning on putting the T in the return line. The photo above is a great validation!

In my view it's best in the return line: as even a tiny air leak in the main feed line will cause issues as the fuel is purely sucked into the injector pump.

Hello folks.

Back on this thread, the new fuel pick up and return pipes, filter basket and gasket arrived at Toyota last week and I collected it from them. Will post some pictures as there are some subtle differences to the assembly and the tank refresh is coming along so it'll hopefully do another 30 years without drama. The reasons for removing the tank was to do a refresh but also check things above (probably the least rusty part of the van, which is good), plus after a long drive there was a noticeable inrush of air so the vent system was blocked.

The tank refresh has comprised cleaning off all the old rust, cracked pads (3 top and 5 bottom ones) and cleaning and degreasing the outside once all the fasteners etc (vents and the like) were off and the openings either bunged or masked. The two loom holding brackets were beyond repairable so these will be replaced, probably with adhesive tabs for cable ties, but will see. I've not removed good paint nor the stone chip compound that was in place but these were keyed for the new layers.

It's then had a liberal covering of Flag Paint's de-rust compound (really like this), then 2 coats of Isopon's Zinc182 rust inhibiting primer (exactly 1 can) then 2 coats of black Hammerite paint. The first coat was thinned quite a lot and I rubbed down with green pad in between the two and wiped down with Hammerite thinners prior to painting.

Due to the tank's size I split the painting into separate occasions for the top and bottom halves so the seam has had a few extra layers and there's been at least a week between coats.

I'm really pleased with the results so far. It's very shiny.

Will post a few pictures of the result but for now here are 'before' shots. Hopefully these will be useful for others contemplating doing a tank refresh.

Top


Bottom


Oh and by the way, the significant difference in the replacement fuel pickup assembly for fitting a heater is that the return pipe is 235mm rather than 250mm so it won't be possible to empty / drain the tank from the heater nor will the heater likely pick up the worst of any crud at the bottom of the tank as it's ~15mm shorter. Might not sound a lot but I think this is useful and I would have shortened the return by about this much. Now there's no need. Will post pictures...  Would still recommend fitting a filter though and I will be doing this, eventually…

I tee’d mine into the main line and put a back flow valve so it can’t suck fuel or I’m hoping air in the event of a leak from the heater side.  

https://youtu.be/59m-RBV0y_Y

Never thought of using the return hose, maybe a dumb question but from where does it return? Excess from the pump?

Just pulled out my tank for other reasons, it was shockingly clean when I drained it, now going to check that inside pickup filter…

I tee’d mine into the main line and put a back flow valve so it can’t suck fuel or I’m hoping air in the event of a leak from the heater side.

https://youtu.be/59m-RBV0y_Y

Never thought of using the return hose, maybe a dumb question but from where does it return? Excess from the pump?

Just pulled out my tank for other reasons, it was shockingly clean when I drained it it. now going to check that inside pickup filter…

Merlin_ wrote:

I tee’d mine into the main line and put a back flow valve so it can’t suck fuel or I’m hoping air in the event of a leak from the heater side.  

https://youtu.be/59m-RBV0y_Y

Never thought of using the return hose, maybe a dumb question but from where does it return? Excess from the pump?

Just pulled out my tank for other reasons, it was shockingly clean when I drained it it.  now going to check that inside pickup filter…

In injection engines the fuel circulates to aid cooling etc.
In diesels there is also a 'spill valve' like a spillway on a dam, that also gets added to the fuel going back!

Hi all,

New here and to driving/fixing a Hiace. I've been on the road in NZ for about a month now in a super hightop 4WD Yokohama motor company campervan. have to say it is one of the best campers I've been in they have literally thought of everything!

Unfortunately, the heater that came with it a 1990 LPG "Propex 1600 compact" has been disconnected I poked around and found the unit was working but the controller had a dodgy rotor transistor on the PCB. Sadly I then found out NZ has some strict gas rules and if I were to reinstall/connect it I could get in some serious trouble, the alternative would be to pay a certified gas installer who then has to check absolutely everything else, i think that rock is best left unturned. On a side note if anyone in NZ is handy with electrics and after a nice garage heater give me a shout.

So I'm now looking to install a diesel heater. After some serious research, i stumbled across this post and Merlin's video. Unfortunately, i don't have the tools or space to drop the tank nor can I use the access from above as an aftermarket floor is in the way. Teeing of the return pipe sounds like a super simple way to do it but I really have 0 idea about doing it. i was hoping one of you who has done it would be kind enough to point me in the right direction and perhaps even be able to send some photos of the tee.

one final point worth note, on my tank I notice a third pipe coming out and then u bending back in or over the top of it. Does anyone know what this is? Guessing it's unusable but a spare pipe would be a nice miracle.

Thanks in advance!

So i attached the following for clarity. Based on answers from Chat GPT I'm guessing the 3rd line is the vent line?

Also asking Chat GPT it told me teeing of the return could be bad news for fuel pressure and flow disruption due to the turbulence the t may cause although I don't understand why this would matter if it's just chucking diesel back into the tank?

Pretty sure a human with actual experience and knowledge would beat ai on this. Any help greatly appreciated!

Yes fuel supply and return the 1kzte has a high fuel return flow 1/2 ltr a min the third one arrowed is fitted with a foam filter for air to keep fuel tank vented .

Thanks, JT69.

Having spoken to a couple of mechanics they reckon there should be no issue regarding flow disruption due to the age of the vehicle. However, newer vans like Sprinters would be a worry.

With this in mind, I'm looking to tee off the return pipe to the heater. As far as i can tell from this post and others who have done it it should just be a case of putting the T junction inline i,e unless im missing something, no other parts such as a check valve are needed as Merlin did? see following:

https://i.servimg.com/u/f89/20/50/19/41/merlin10.png

My only questions now are:

Is there any worry about pulling the fuel out of the return pipe itself? we would only be using this when the engine is off so we shouldn't be disturbing the flow back to the tank when the engine is running but I'm wondering if there is any issue with the pump pulling from both the fuel tank and engine until the pipe from the engine is dry?

Also, would the fuel being pushed back into the tank be forced toward the diesel heater when not in operation or would it simply take the path of least resistance to the tank?

Thanks Again!

Did you check the pick up filter in the tank there is an access through the floor to the tank unit , also there are two filters on the IP pump (youtube) , tee piece in return pipe I do not know if it goes to the bottom of the tank if not it will pull air up return pipe.