Womala Thermostat LR121420 for Land Rover Range Rover Sport

Product Overview

The Thermostat and Housing Assembly LR121420 is an OE-grade engine cooling component engineered for the 3.0L Ingenium AJ20P6 petrol inline-six engine (MHEV/PHEV) in select for Land Rover and for Jaguar vehicles . This assembly regulates coolant flow between the engine and radiator, maintaining optimal operating temperature and ensuring efficient combustion. An internal degas valve failure in the thermostat assembly can trigger DTC P0128-00 (thermostat range performance) – LR121420 is the specified replacement for this known issue . The assembly has an opening temperature of 97°C .

Key Features

• Complete housing assembly – includes thermostat, housing, and seals

• 97°C opening temperature – factory-calibrated for 3.0L Ingenium petrol engines 

• OE-grade quality – genuine Land Rover specification; also available from OE suppliers including Wahler and Motorad

• Direct-fit replacement – matches factory mounting points and coolant line connections

• Common failure fix – resolves DTC P0128-00 (thermostat range performance) 

OE Cross-Reference

Aftermarket equivalents: Wahler 412113101 · Motorad TA4200 · Borg & Beck BBT602 

Vehicle Fitment

Known Application Note (SSM75463): Models affected by thermostat DTC P0128-00 include Defender / L663, Discovery / L462, Range Rover / L405, Range Rover Sport / L494, and Range Rover Velar / L560 .

⚠️ Important: LR121420 is specifically for the 3.0L Ingenium petrol inline-six (AJ20P6/AJ22P6) – MHEV and PHEV variants. Not for diesel, 2.0L Ingenium, 5.0L V8, or earlier AJ126 V6 engines .

Signs of Failure

• Check engine light – DTC P0128-00 (thermostat range performance) 

• Engine overheating – thermostat stuck closed, restricting coolant flow

• Engine running too cool / slow warm-up – thermostat stuck open 

• Poor heater performance – cabin heater blows cold air when engine is warm 

• Increased fuel consumption – engine not reaching operating temperature 

💡 This thermostat assembly was subject to a Land Rover Technical Service Bulletin (SSM75463) – premature failure of the internal degas valve can trigger DTC P0128-00. The remedy is replacement of the thermostat assembly, not a software update . For 3.0L Ingenium petrol engines, a new O-ring (LR140792) is recommended when replacing the thermostat .

Critical – Verify Your VIN Before Ordering

Thermostat assemblies are VIN‑, engine‑, and model‑year‑specific. LR121420 is for the 3.0L Ingenium petrol engine (AJ20P6/AJ22P6) – not for diesel or V8 variants. Provide your VIN – our team confirms exact compatibility before dispatch. We cannot accept returns for misordered parts without VIN verification.

💡 Installation Tip: Professional installation recommended. When replacing the thermostat, renew the housing O-ring (LR140792) . After installation, top up coolant with OEM-specified fluid, bleed the cooling system to remove air, and clear any stored DTCs .

Technical Specifications

Why Choose Us

Contact us for bulk orders or VIN‑checked quotes.

Specifications subject to change; images for reference only.Aftermarket replacement – not affiliated with Jaguar Land Rover.

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