Land Rover Range Rover Evoque: Plastic Thermostat Housing Coolant Leak (Si4 2.0T Petrol)

The Si4 2.0-litre turbocharged petrol engine uses a plastic integrated thermostat housing that is prone to cracking along the sealing face and around sensor bosses as the material fatigues from repeated thermal cycling. Coolant loss is often gradual and may not trigger an immediate warning light, leading to undetected low-coolant conditions and potential overheating. This is widely documented across the LR4, Range Rover Sport, and L538 Evoque that share the same engine family. Land Rover later revised the housing material in a superseded part number.

• Coolant loss requiring frequent top-ups without a visible puddle under the car
• White or crusty staining on the engine top around the thermostat area
• Temperature gauge creeping above normal midpoint, particularly at idle
• Sweet coolant smell from the engine bay when stationary after a drive
• Overheating warning light in advanced cases if coolant level drops critically

1. 1

   Inspect the top of the engine for coolant residue (white or pinkish staining) around the thermostat housing on the front-right of the engine.

2. 2

   Check the coolant reservoir level and look for brown or oily contamination.

3. 3

   Ask the seller if coolant has been topped up.

4. 4

   During the test drive watch the temperature gauge for any fluctuation above the normal mid-point.

5. 5

   If a workshop inspection is possible: A pressure test of the cooling system will confirm any seeping cracks.

Parts involved: Thermostat.

$550 to $1,400 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Has the thermostat housing ever been replaced, and was the updated revised-material part used?”
• “Has coolant needed topping up between services, or has there been any overheating incident?”

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.