Underslung Water Tank Melted!

[Andrew Wilkinson]

As part of my conversion I've had an under-slung fresh water tank fitted to my T6 LWB. It's the long slim tank which fits next to the exhaust almost down the centre of the van.
The first one a I had fitted was not very secure and melted against the exhaust.
I have since built a more secure way of fixing it and it feels much more solid. It is still, however, very very close to the exhaust. I assume that all of them must be this close and that someone is going to have an ingenious way of preventing this one from melting??
I'm concerned that under braking the weight of a full tank will cause enough movement to push the tank a few millimetres forwards and touch the exhaust.
Does anyone have any idea of perhaps an adhesive backed material which will prevent the heat getting to the plastic?
Cheers.

 

[oldiebut goodie]

Exhaust wrap along the pipe alongside the tank? Some high performance products available - 900°+, double layer it. ( At least you are getting free hot water!)

 

[Skyliner33]

Motorcycle Fairing Panel Exhaust Engine HEAT SHIELD Self Adhesive Sheet New | eBay

 

[Ads_Essex]

Blimey. What sort of temperature is the water getting up to? Would that cause issues with bacteria?
I ask because I’ve been looking at these myself.

 

[Andrew Wilkinson]

The water is fine. I think that it is the way in which the previous tank was fitted. It had moved and allowed direct contact with the exhaust. That had melted a hole.
I had another look at the mounting of the new tank last night and the movement is now minimal. The tolerances are very tight so, for the sake of £12 or so I might well follow the suggestion of the motorcycle heat shield.
Thanks again for the helpful advice.

 

[Andrew Wilkinson]

Blimey. What sort of temperature is the water getting up to? Would that cause issues with bacteria?
I ask because I’ve been looking at these myself.

While the mounting has been an issue, I'd still go for an underslung tank. The extra storage inside the van and the ease of filling and emptying is worth the extra work.

 

[Ads_Essex]

While the mounting has been an issue, I'd still go for an underslung tank. The extra storage inside the van and the ease of filling and emptying is worth the extra work.

@Andrew Wilkinson where is your filler mounted? Do you have any photos? And how did you get on with the meter in the end - did you manage to find an extension cable?

 

[Andrew Wilkinson]

Yes, I found an extension cable.....to my embarrassment it was in the bag which came with the CBE unit! It seems that they supply all of the cables for the 'add on' bits such as probes for fresh and waste water tanks. Fortunately I was able to cancel the order for the new cable I'd found.
The probe works fine. If you don't fit a probe there is an annoying little flashing light on the CBE unit which tells you something is wrong with the probe!
The filler cap is fitted inside the rear unit inside the van, I didn't want anything cut through the outside of the van to spoil the lines. I'm afraid that I don't have any photos but pretty straightforward to go through the floor behind the offside rear wheel. We have a bullfinch shower outlet in there too.

 

[rod_vw]

I have fitted four of these tanks (assuming that yours is the Autosleepers type from Autocraft @ Staveley or a similar supplier) never had any issue with them getting too hot. I always mount them with a wide strap around the specific mounting areas and bolt up to existing threaded holes in the chassis. I always use this tank centre for waste with the fresh water tank being the larger version that fits around the left side and in front of the spare wheel.

On our current T6 (Euro 5) the silencer is larger and does only clear the tank by a very small amount but has never given any problem.

Non of my vehicles have been Euro 6 with Adblue, maybe the use of that and DPF Regeneration makes the exhaust run a lot hotter at that point.

Re my filler, I use the California combined water and EHU unit and fit it exactly the same as a Cali one fits measured from the rear of the vehicle. Being a LWB this does not foul the sliding door. This one is on a T5 with factory high roof.

 

[Ads_Essex]

@rod_vw when you say “close”.. how close are you talking about? I’ve bought the centre-chassis tank from Autocraft and am just sizing it up before I drill holes for the gauge / hoses etc; the tank sits about 20mm away from the exhaust centre-box at best, it being around 10mm (when centred) so that there is equal space all around the exhaust box. Assuming the exhaust is a similar type to yours (I’m EU5 too) I take it this amount of space is adequate?

 

[Ads_Essex]

These gaps - fore and aft the centre-box.
(Edit to add - NB: the tank sits flush with the heatshield once the clamps are installed and tightened up)

 

[Eli]

without seeing it properly, it is possible to 180 the tank so the the left hand side of the tank is actually supposed to fir in the recess on the right of the image. the reason I ask is the tank is tapered on the left corner (closest to camera)

 

[Ads_Essex]

without seeing it properly, it is possible to 180 the tank so the the left hand side of the tank is actually supposed to fir in the recess on the right of the image. the reason I ask is the tank is tapered on the left corner (closest to camera)

Good shout mate but I’ve tried that already - the recess for the centre-box isn’t big enough when rotated.

 

[Andrew Wilkinson]

Yes, I found the tolerance was only about a finger width at each end. I used angle iron to make a frame to hang the tank with another piece fixed from the rear hanger at 90 degrees to brace the tank from shifting under acceleration and braking especially when part full.
I then followed one of the links in this thread and bought some motorcycle fairing heat shielding. Great stuff and has given me peace of mind.

 

[Ads_Essex]

Yes, I found the tolerance was only about a finger width at each end. I used angle iron to make a frame to hang the tank with another piece fixed from the rear hanger at 90 degrees to brace the tank from shifting under acceleration and braking especially when part full.
I then followed one of the links in this thread and bought some motorcycle fairing heat shielding. Great stuff and has given me peace of mind.

After finding that I couldn’t get good discipline with the plastic-encased webbing strap (whatever it’s called) I’ve strapped the tank up with threaded rod and short lengths of said webbing.

The exposed section of rods are around 200mm long and, due to their narrow (M8) gauge, can be bent.

There’s still movement - I’m not convinced that the gap between the tank and the centre-box will remain.

Can you share any photos of your setup @Andrew Wilkinson?

 

[Bryn23]

geez thats close,

i used Exhaust wrap around the exhaust were the waster water pipes and connections were close on my CAK tank,

its a pain in the ass to fit the wrap under the van, that self adhesive heat shield looks like are good solution

 

[Andrew Wilkinson]

I'm not in the country at the moment but as soon as I get home I'll post some pics. The motorcycle heat shield stuff is worth getting.

 

[Andrew Wilkinson]

Hi,

I said that I would try to take some pictures of the set up under my van with the motorcycle heat shielding.
I hope that this works as I'm not particularly skilled at this IT business!



This is the leading edge of the tank.



and this is the rear of the tank.
The flexible heat shield material is very easy to use and being self-adhesive also very easy to cut and apply.



I then rigged a piece of angle iron (two actually as I didn't have a piece long enough) to counter the potential movement under braking and acceleration.

After the first trip I checked and although the tank has clearly touched the exhaust slightly, the heat shielding has protected it really well.

I hope this helps.

 

[rod_vw]

@rod_vw when you say “close”.. how close are you talking about? I’ve bought the centre-chassis tank from Autocraft and am just sizing it up before I drill holes for the gauge / hoses etc; the tank sits about 20mm away from the exhaust centre-box at best, it being around 10mm (when centred) so that there is equal space all around the exhaust box. Assuming the exhaust is a similar type to yours (I’m EU5 too) I take it this amount of space is adequate?

My apologies for not replying sooner, I've been away on holiday and missed this thread.

I have this tank fitted to a 2016 T6 (Euro 5) and know that there is little clearance between the tank and the centre silencer but mine is fitted with the normal wide straps to the existing threaded holes in the chassis and has no additional shielding from the exhaust. I have seen no sign of melting caused by the exhaust. The camper has now covered 30,000+ miles since conversion some of which on very hot journeys in the South of France.
I did have a slight surface melt on the front of the tank from the Eberspacher exhaust which is mounted under the left side where the adblue tank would be, that was cured with a deflector plate in front of the tank. To cause this the Eberspacher had been running all night whilst in cold weather in Scotland late Spring during 2018.

I know it looks frighteningly close but in my case experience has proved that it is not a problem.

I've fitted three of these tanks on T5s in the past which admittedly have a slightly shorter centre silencer all without problem. In each case the straps that I have used to suspend the tank have been made from fairly thick aluminium wrapped in wide gaffer tape to prevent chaffing of the tank, the straps being wide enough to prevent the tank from moving fore and aft.

Rod

 

[Ads_Essex]

Cheers @Andrew Wilkinson and @rod_vw for the detailed responses.

I’m yet to check whether mine have moved much, but you’ve given me some ideas should I find the tank has been touching against the exhaust.