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Autopapyrus · Range Rover Sport (L494) 3.0 Diesel (2015)
https://autopapyrus.com/guides/land-rover/range-rover-sport/installing-a-webasto-hydronic-2-d5s-pre-heater/
Compiled automatically from service literature and owner experience. Specs are for the typical configuration — check them against your exact car before you start.

Range Rover Sport (L494) 3.0 Diesel (2015): Installing a Webasto Hydronic 2 D5S Pre-Heater

The Hydronic 2 D5S is plumbed into the cabin heater circuit, in parallel or in series with the factory system. Coolant is drawn from the engine circuit, heated in the pre-heater's boiler and returned. This warms the engine block and the heater core at the same time. The exact tie-in layout on this vehicle depends on the engine version and trim level, so the proven general principle is given below, and the tie-in points are determined on the vehicle.

Difficulty: Hard Time: 1-2 working days (8-14 hours) Steps: 12

Parts

9
№Part
01 Hydronic 2 D5S liquid pre-heater (diesel, 12 V) with installation kit
02 Fuel metering pump
03 Fuel pickup from tank or tee into supply lineone of the options
04 Silicone coolant hoses, 16-18 mm inside diameter
05 Wide-band hose clamps
06 Exhaust muffler and pre-heater exhaust pipe
07 Control unit (timer or GSM module)
08 Fuses and relaysfrom the kit
09 Coolant (antifreeze)

Tools

12
  • 8-19 mm socket and wrench set
  • torque wrench
  • hose clamp pliers
  • spring clamp pliers
  • crimping tool for terminals and connectors
  • multimeter
  • drill and metal drill bits
  • fitting kit for tapping into the fuel line
  • coolant drain pan
  • zip ties
  • heat-resistant corrugated conduit
  • factory-spec coolant mix for topping off
There's a full repair manual for this car Every system, wiring diagrams and torque specs — not just this job. Haynes AutoFix (online) and 1 more. See manuals →

Step by step

12 steps
  1. Preparation. Disconnect the negative battery terminal, taking into account the Start/Stop system and modules that are sensitive to loss of power. Let the engine cool completely. Remove the lower undertray and, if necessary, the air duct and the engine cover.
  2. Choosing the mounting location. The pre-heater is mounted in the engine bay or in a wheel arch, with protection from splashes, water and dirt. Keep the distance to the exhaust manifold, turbocharger and catalytic converter at no less than the minimum specified in the kit's installation instructions. Position the pre-heater so that air can escape from the boiler while the system is being filled, meaning the coolant connections point up or horizontally.
  3. Find the two hoses on the vehicle that run from the engine to the cabin heater core through the bulkhead. One is the hot coolant feed to the heater, the other is the return. Determine which is which by flow direction: the feed leaves the engine, the return goes back to it. Work out the length of hose that needs to be cut.
  4. Draining the coolant. With the engine cold, open the expansion tank, place a pan underneath, and drain 1-2 liters (1.1-2.1 qt) of coolant through the lower radiator hose or the heater hoses so that coolant does not spill out during the tie-in. Do not pour coolant down a drain or onto the ground.
  5. Connection layout. Install the pre-heater into the heater feed hose: coolant flows from the engine to the pre-heater inlet, and the pre-heater outlet connects to the hose that continues on to the heater core. The pre-heater's circulation pump must work in the same direction as the factory flow. If you use a layout with a check valve, install the valve so that the engine's main pump does not push coolant through the idle pre-heater. Check the direction of the arrows on the valve and pump before tightening the clamps.
  6. Tie-in. Cut the factory hose with a clean, square cut, insert the tee or the silicone adapters from the kit, and secure them firmly with wide clamps. The tightening torque for worm-drive clamps is low: use the figure in the kit instructions, most often in the range of 2-4 N·m (18-35 lb-in). Do not overtighten and crush the silicone.
  7. Fuel line. The pre-heater needs a diesel fuel supply. The preferred option is a separate fuel pickup from the tank through a fitting installed in the fuel pump cover, or a tee into the low-pressure supply line with a metering pump. Do not tap into high-pressure lines or into the return line, where the fuel is hot. Install the metering pump at the angle specified in the instructions (the mounting angle is given in the installation diagram), in an area protected from heat. Parts suppliers offer ready-made kits, but on this model the factory fuel module does not always allow a tap-in, so if in doubt, choose a separate pickup.
  8. Exhaust and air supply. Route the pre-heater exhaust pipe downward under the vehicle, with a slight downward slope and a hole for condensate drainage, away from plastic parts and fuel lines. Aim the outlet so that the gases do not enter the cabin air intake or the pre-heater's air intake. Protect the combustion air intake from dirt and splashes.
  9. Electrical. Run the main power positive lead from the battery through a fuse, with the rating given in the installation diagram (usually 20-25 A for the D5S). Connect the ground to the body at a cleaned spot, using contact grease. Route the wiring in corrugated conduit, away from sharp edges and hot parts. The control unit (timer, remote or GSM) is installed in the cabin, and its wire is passed through a factory grommet in the bulkhead.
  10. Filling and bleeding the system. Top off with coolant that meets the factory specification, up to the correct level in the expansion tank. Turn the ignition on, then start the engine, set the heater to maximum heat and switch on circulation. Warm the engine up to operating temperature, let the thermostat open, and rev the engine a few times. Watch the level and top off until it stabilizes. Air pockets in the pre-heater boiler cause overheating and emergency shutdown.
  11. First start of the pre-heater. Start the pre-heater from the remote or timer and make sure the pump is running, fuel is being delivered and heating begins. Check all clamps and connections for leaks once heated. With the pre-heater running, the coolant in the hoses should warm up to 70-80 °C.
  12. Function check. Stop the pre-heater, let it cool and check the coolant level again. Connect a diagnostic tool and make sure there are no fault codes for the engine or the climate control system. Take a test drive and check the level and the absence of leaks once more.

Common mistakes and warnings

  • This is a complex job that involves the fuel system, the cooling circuit and the electrics
  • A poor tie-in leads to fuel leaks, fire or engine overheating
  • If you lack experience, leave the installation to a specialist shop
  • Do not run the pre-heater in a closed garage or while refueling: the exhaust contains carbon monoxide
  • If the vehicle is under warranty, installing a pre-heater outside the dealer may affect warranty coverage
  • Take exact tightening torques, tie-in layouts and wire gauges from the pre-heater's installation instructions and the vehicle manufacturer's service information