If your going to fit a diesel heater in your van then read this.


hardware modifier
I feel that I have to make this thread after watching maybe 4 or 5 videos on YouTube of people fitting these or the Chinese heaters in self build camper vans.
There is a rubber seal on the bottom of the units for a good reason, it's to keep the poisonous stuff out.

I did a test.

With the exhaust pipe connected but the device not bolted down to the floor it was obvious straight away that not only did fumes from the exhaust get in but also the smell and vapour of unburnt diesel came in the van after I returned 15 minutes later to check on the progress. There was moisture on rubber gasket, a mix of steam and unburnt diesel.

Mounting these heater on legs so the base of the heater is not sealed against the floor IS dangerous. I've seen them with the Chinese "stainless" exhaust pipe that is just pressed and badly spot welded in the van for maybe 3-4 inches before it goes out the bottom.

Before fitting mine I bunged one end and checked to see if it would indeed be gas tight, they are not sealed and have very small gaps along the length. This would allow for carbon monoxide to leak in the van of any of this pipe was inside the van.

Secondly fitting these heater on stilts and not having a pipe connected to the inlet IS dangerous. If these heaters flame out for any reason they can sprew thick white unburnt diesel smoke out of the inlet filling your van with poisonous vapours.

Why shortcut on a device that could easily kill you while you sleep if it fails?
Don't gamble with your lives or others when it comes to these devices.
Make time to fit it correctly and don't bodge it to just to save time or not to drill a larger hole in the vehicle.

If you are a passenger in a vehicle and you smell unburnt diesel inside the van after starting up a heater then say something, don't let it go unnoticed.

Enjoy your van and your travels people and do it safely and fit your heaters properly.
Cheers :cheers:


New member
Good post. I installed the Espar D2 but don't want to bet my life on it or my install so I also have a smoke/CO detector in the van.
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Well-known member
Following the Espar instructions for marine installations enables you to safely install the heater without sealing flush to the floor.

There are a few points that are required to be followed (among others).

1. The corrugated flex tubing that comes with the Espar is not allowed. It is tack welded & crimped spiral strip wrapped into a tube and can be leaky. It also does not seal well because of the tube corrugations beneath the clamp holding it to the Espar outlet. The Chinese tubing I have seen has a full welded seam and does not have corrugations under the clamping area. It is an improvement over the Espar tubing - but is still quite thin.

2. The combustion air must come from the outside - or you do risk backflow of fumes into the living space when the blower turns on/off and if there is a combustion backflash/pop.

3. No leaky muffler inside. Marine mufflers are 100% sealed cylindrical tube shelled units.

4. Use properly sealing thru-hull fittings for the intake and exhaust gases.

5. Fuel lines are made of copper rather than the plastic/nylon lines commonly seen.
The Espar exhaust tubing is far, far better than the crap thin tin supplied in the Chinese heaters. I've never had any issue with the Espar pipes sealing; if concerned use a bead of hi-temp RTV.

There are tons of people on youtube and forums who install heaters poorly, being the US Propex distributor I have seen some of the worst crap installs possible - and then they complain when things don't work correctly. In the VW groups people are installing the cheap Chinese fuel tanks INSIDE CLOSETS. Then running K1. No problem there...:rolleyes:


Well-known member
If you have repaired a number of airtronics, you will have undoubtedly seen a spiral groove made in the exhaust stub by the exhaust gases following the spiral wrap of the tube up past the clamp. Also, you will have seen the soot stains on the mounting plates where these gases have exited the tubing. You will have also dealt with a fragile, un-spiraling, leaky old exhaust line. The Espar tubing is just fine for outside use but even Eberspacher says it is unsuitable for interior runs.

While I have not seen all Chinese exhaust tubing what I have seen was of good quaility, stainless, full welded seam, thicker than the Espar metal, and it does not have the leak prone corrugations in the clamp area. It is however MUCH less flexible than the Espar tubing.
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Nope, I have never seen this. Fragile is the word better used for the Chinese tin. When I can smash it in my fingers, that's not quality.
Nope, I have never seen this. Fragile is the word better used for the Chinese tin. When I can smash it in my fingers, that's not quality.
The same could be said for the Espar SS exhaust tube. It too is fragile. It doesn't make it crap. It's just not meant to be squeezed on like that.
Hmm. Must be something new, because the 6 M roll of it I have here is super quality.
No matter how good the quality of the corrugated tubing (I also think it's bad), the muffler leaks by design. There are vents, at least in the T1N, that lead from under the chassis (exhaust exit point for many installs) right up into the cabin. I have breathed enough bad fumes in my life and want to minimize them from here, so I welded the leaky muffler until it was sealed, and threw away the corrugated tubing, replaced with 1" stainless solid wall. Someone else posted about using copper instead- that would be equally effective, braze-able, cheaper, and available at any hardware store.
They must just be pinching pennies, not to provide the marine quality muffler with all sales. I would have purchased had I know about it at the time. Might they also provide different tubing for a marine install?


New member
Just planning my build now, gathering parts....

I’m giving serious consideration to installing it under the van.

I really think the best location for it is under the passenger seat. It's really wasted space. If you do the install proper with the heater base flushed to the van's floor and it's properly sealed you don't get any of the issues people are discussing. Even if the seal between the heater's outlet and the Espar's corrugated exhaust pipe and the exhaust pipe to muffler isn't perfect. It really is a don't care.


Can anyone tell me that using regular fuel tubing would be improper for this install rather than the small poly tubing? The I D is similar in size. Think that the regular tubing will be more robust.


New member
Can anyone tell me that using regular fuel tubing would be improper for this install rather than the small poly tubing? The I D is similar in size. Think that the regular tubing will be more robust.
Stick with the small poly tubing that comes with the Espar. I'm sure fuel pressure is a consideration with that small, hard tube. From a robustness standpoint, it's plenty robust, provided it doesn't get kinked and you route the line properly. I've spent hours underneath a Sprinter routing various lines. There are plenty of safe places to route things of this sort, especially with a small diameter tube like this.

I ran my Espar fuel line all the way from the far right rear of a 170 up to the fuel pump. I believe about 14' of fuel line and it's been problem free.

The important consideration is where the fuel line passes through the van and any other obvious areas where heat or abrasion might occur. I did use heat protective sheathing on a short section of my fuel line where it was somewhat near the exhaust just for precaution. You can also use short sections of heat shrink or even that expandable sheathing for wiring in areas where abrasion might be a concern. Deburr any holes you drill in the van for this and consider using a rubber grommet if the fuel line does have to pass through the van floor.
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2013 144
I couldn’t get a good clamp seal with the poly tubing, so I used high pressure fuel line from Napa. It’s a short run (I mounted my heater behind the driver’s seat) and it fits tight enough that I could have skipped the hose clamps. No problems. I can’t see where it would make a difference.

This I think is what I used.




Thanks guys, I ran out of steam will finish tomorrow. Dealing with a leak in my foundation and trying to finish my heater install.


2014 GWV Legend 3500 I4
My upfitter used larger fuel line rather than the official Espar stuff. I spent two years chasing occasional flame-out issues. I finally took it to Thermo-King. They said "wrong fuel line". They tore it out and replaced with the correct stuff. Heater has worked perfectly ever since.

Use what Espar says. It matters.

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