Complete VW Transporter Diesel Heater Installation Guide (Autoterm 2kW, Eberspacher Step-by-Step)
Looking to install a diesel heater in your VW Transporter? This complete step-by-step guide shows you exactly how to fit an Autoterm 2kW heater into a VW T5 or T6.
We cover everything from removing the fuel tank and installing a fuel pickup, to mounting the heater, routing ducting, and wiring the system safely.
Installing a diesel heater in your VW Transporter is one of the best upgrades you can make for year-round van life.
An Autoterm 2kW heater is installed in our guide but the Eberspacher heater follows the same procedure.
Difficulty: Intermediate
Time required: 5–7 hours
Vehicle compatibility: VW T5, T6, and T6.1 Transporters
Tools & Materials Checklist
Before you start, make sure you have:
- 7, 8, 10, 13 & 14mm sockets
- Torx T20 bit
- Riv-nut pulling tool
- Fuel tank connector for T6.1 only (link click here)
- Snips/side cutters
- Pliers
- Stanley knife
- Drill
- Hole saw (70mm)
- Some safe way of lifting your van (jack, axle stands)
- Some safe way of supporting a fuel tank (empty tank weighs about 10kg but a full tank can be 80 - 90kg!)
- Bucket
💡 Tip: Having everything ready beforehand will save you hours mid-install
Choose Your Heater Location
The most common install location is:
- Externally mounted, under the driver seat (VW T5/T6)
Why?
- This is the location VW use when they factory fit a diesel heater
- Mounting holes for heater cradle are present
- Easy routing for exhaust and intake
- Keeps heater hidden and protected by the undertrays
- Tried and tested method
Disclaimer: We will not be held responsible for any injuries or damages resulting from advice given in this guide. Standard engineering practices and common sense should be used alongside with our guide.
📍 Step 1: Lift Van & Remove Undertrays (VW T6 Prep)
Lift the van up off of the ground 400mm or more.
Remove surround from the diesel and Ad-Blue fill point with a T20 bit. Remove 1x 10mm head bolt from diesel fill pipe and 2x 10mm nuts for Ad-Blue fill pipe. Both fill pipes should now be loose.
Get under the van, remove black plastic undertray from beneath passenger seat and also the long undertray covering the fuel tank. The under tray beneath the drivers seat also needs to come off.
💡 Tip: If you are struggling to unwind the round VW undertray fasteners, we supply some spares in our kit so they can be removed with side cutters/pliers.
📍 Step 2: Remove Fuel Tank (VW Transporter)
The fuel tank is secured by 3 straps and 6 (14mm) bolts in total. First, remove the middle strap. Then support the fuel tank - the tank will need lowering carefully.
With the support in position, remove the outer two straps and drop the rear edge of the fuel tank down just enough to allow access to the fuel sender on the top of the tank.
📍 Step 3: Install Diesel Heater Fuel Pickup (T6.1 Method)
For T6.1 Transporters, on top of the fuel sender there will be a blanked off pipe that we will modify. (for earlier vans, a guide will be uploaded soon) You can see the blanked off pipe on the right hand side of the picture below.
You need to cut the cap/nipple off the top of this pipe to allow the new fuel feed adapter to fit.
Using the black rubber pipe joiners, attach the transparent fuel pipe to the adapter and push the adapter on to the pipe you just opened up. Make sure the hose is pushed fully into joiner.
💡 Tip: Use some silicone spray on the inside of the rubber joiners to allow the fuel hose to slide in easier. We mark a few lines on the fuel pipe with a permanent marker to show how much has been inserted into the joiner.
The transparent pipe is then guided alongside the existing VW blue and black fuel pipes, you will be able to make use of some spare/empty pipe clips next to the existing pipes.
The new fuel pipe is to be routed above the Ad-Blue tank so we can work on it later.
If you are happy with the routing and happy that you have tightened the fuel adapter joints then the fuel tank can be lifted back up into it's correct position and tightened up.
Be aware that the fuel may syphon out of the tank if the exposed pipe is left too low, ie on the floor. Best put the pipe end in a bucket just in case.
📍 Step 4: Install Fuel Pump & Fuel Line Routing
We install a riv-nut as shown below to allow the fuel pump to be secured.
This riv-nut is just above the Ad-Blue tank, looking towards the back of van. You will be directly underneath the passenger seat at this stage.
Once the riv-nut is installed, the fuel pump can be put in its mount and installed. Pay attention to the flow arrow. Obviously the fuel flows from the fuel tank to the diesel heater core.
The Inlet of the fuel pump needs to be lower than the outlet, this is done by tilting the bracket as show below.
Trim the fuel pipe and make the connection with the inlet (right hand side) of the fuel pump. The remaining section of pipe is the routed above the heat shield and across to the area beneath the drivers seat.
📍 Step 5: Cut Heater Intake & Outlet Holes (70mm)
We need drill some holes. The first hole will go in the drivers side step, use the plastic vent cover as a guide and drill a 70mm hole as shown. This is the air intake for the recirculated warm/hot air.
Depending on where you want the heater outlet to be, we now drill another 70mm hole. In our example this hole for the outlet pipe goes under the drivers seat next to the rubber grommet in the floor.
Beside this hole, take note of the stud where we have attached a black cable. This is a chassis bonding point provided by VW, so our negative (black) wire will go here when we get a little further.
Prime the holes you just made and fit the plastic step if you removed it.
Put the ducting on the plastic vent and feed it through the hole. Secure the vent with screws and pop the cove into position.
📍 Step 6: Mount the Diesel Heater Unit (External, Under Seat)
Go back to the passenger side and re-assemble the Ad-Blue and diesel filler surround.
Now, its time to prep the heater core. Attach the mounting bracket to the heater core.
We find straightening this locating tab a little with some pliers helps it to fit better.
Time for two more riv-nuts to be installed, this time under the drivers seat.
(Riv-nuts + heater installed for reference)
Then attach the heater with the stainless bolts plus oversized washers.
The heater can only be installed one way round. The 60mm inlet is at the front of the van, the 60mm outlet points towards the rear of the van. The two metal stubs in the image above are for the heaters combustion chamber, forward is the air intake, the rear on is the exhaust.
The fuel pipe that you fed over the heat shield and over to the drivers side can now be connected to the heaters core.
📍 Step 7: Install Exhaust, Intake & Ducting System
The black plastic air intake with muffler is now installed as below. (note you can shorten this pipe with a Stanley blade, do not cut the muffler end though)
The 60mm recirculation air hose is fitted too, use the Jubilee clips but not too tight or you will cause the fans blades to bind on the casing.
The cable from the heater to the fuel pump goes in now, it runs alongside the fuel hose you have just installed. The fuel pump wire is far too long but it cannot be cut as it has a connector plug on the end so it can be coiled and cable-tied neatly next to the fuel pump.
The fuel pump wiring harness is not polarity sensitive so you can put the wires either way round on the connector.
The air inlet and recirculated air hose should look like this.
The exhaust pipe and 60mm heater outlet hose go on next.
The exhaust silencer can be attached to the heat shield as below. Its exact position just needs to be far enough away from the vans exhaust to avoid rattling and also away from direct contact with the exhaust munt rubbers.
Be sure to mount the exhaust outlet in such a position that it is not going to blow straight back at the heaters air intake. Care should also be taken to ensure that the exhaust fumes can exit the underside of the van without restriction.
📍 Step 8: Wiring the Diesel Heater (Power & Controls)
The main parts are all now installed.
The wiring harnesses clip into the connector blocks on top of the heater core.
Bringing the electrical wires and the remote wire up and into the cab can be done via the grommet beneath the drivers seat (or passenger seat). It will depend on your battery setup as to how you proceed. Similarly the remote cable can be run to any position you need it.
Refer back to the chassis bonding point mentioned earlier in step 5 for a suitable place to connect the heaters negative wire.
Connect the heater control panel in your desired location.
Once the electrical connections are made, switch the heater on, check everything is ok.
Some pics of various heater outlet and remote control configurations we have used.
📍 Step 9: Final Assembly & Testing
Once you are happy that everything is working as it should, re-install the undertrays and lower the van. Congratulations you've installed your diesel heater.
Don't forget to install a carbon monoxide detector in your van
⚠️ Common Mistakes to Avoid
- ❌ Drilling without checking underneath
- ❌ Poor exhaust routing
- ❌ Loose fuel connections
- ❌ Skipping rust protection
Common Diesel Heater Installation Problems (and Fixes)
- Heater won’t start: Check fuel supply and battery voltage (read more here)
- Excessive smoke: Normal on first startup, but persistent smoke may indicate poor combustion
- Noisy pump: Ensure correct mounting angle and isolation
- Air leaks: Check ducting connections and seals
❓ FAQs
How Much Does It Cost to Install a Diesel Heater?
A typical diesel heater installation in a VW Transporter costs:
- Autoterm or Eberspacher kit: £600–£800
- Additional parts/tools: £50–£150
Installing it yourself can save a significant amount of money, but it’s important to ensure everything is fitted safely and correctly. A professional supply plus install of a decent branded heater will cost over £1000
Can I install a diesel heater myself?
Yes — if you're confident with tools and follow instructions carefully.
How long does installation take?
Typically 5–7 hours for a first-time install.
Is it safe?
Yes, when installed correctly with proper exhaust routing and sealing.
Does it drain the battery?
Very little — especially once running.
Can you install without dropping fuel tank?
No. You will have to lower the tank sufficiently to get access to the top of the fuel sender. By far the easiest way is to fully lower the tank.
Is it safe to sleep with it on?
Yes, absolutely. We advise installing a thermostatic controller to keep the van at a comfortable temperature during use.
Tip: Always install a carbon monoxide detector when using a diesel heater in your campervan.
🧠 Pro Tips
- Run everything loosely first, then tighten once aligned
- Take photos during install (helps if troubleshooting later)
- Label wires and connections
- Don’t rush — most mistakes happen when hurrying
🏁 Final Thoughts
A properly installed diesel heater completely transforms your campervan — making it usable all year round.
Take your time, follow each step carefully, and you’ll end up with a safe, reliable heating system that lasts for years.
🛒 Need the Parts?
Make sure you’re using a complete, high-quality heater kit with all required components — it makes installation far easier and avoids compatibility issues.