Symptoms
A slow coolant drip from a crack in the plastic thermostat housing, low coolant, rising temperature.
The fix, step by step
- Drain the coolant, remove the engine cover, air box and intake, the throttle body and the hoses to the housing, then the eight T30 Torx bolts; the assembly is sealed by three O-rings, not sealant.
- Fit the new LR005631 assembly as one piece (one owner split it, damaged an O-ring and made a new leak) and tighten the bolts evenly.
- Refill with OAT coolant and bleed patiently through the expansion tank and bleed screw, ideally with a vacuum filler.
Tools & part numbers
- 6/8/10/13 mm sockets, T30 Torx, wobble extensions, pick, vacuum coolant filler
- LR005631
- LRN2279 coolant
Where to buy the parts
Hunting a used or discontinued part? Search eBay Motors for Land Rover LR3 / Discovery 3 parts →
Rated for a competent home mechanic with a decent tool kit. Confirm torque figures, fluids and procedures against the factory service manual for your VIN, support the truck on stands rather than a jack, and work at your own risk (disclaimer). Some parts links are affiliate links, which pay us a small commission at no cost to you.