Land Rover Engine Coolant Thermostat Assembly - Genuine Land Rover LR105974

Product Information

Thermostats are a simple device which regulates coolant flow through the engine. When cold it will stay closed, stopping coolant flow and helping the engine warm up faster. Once up to temperature, it will open and allow normal coolant flow and maintain proper engine temperature. Always install with the 'jiggle pin' bleed valve at 12 o'clock when possible.

For many applications, multiple temperature ratings are available. These ratings denote when the thermostat opens, and in extreme climates different temperature ratings can be used to assist the vehicle in maintaining proper temperatures. In very hot desert climates for instance, a lower temperature rated thermostat may be preferred.

There are two types of thermostat failures:

Thermostat stuck open (most common): Coolant will flow through the engine constantly from cold, preventing the engine from reaching operating temperature. Usually this means a rich mixture resulting in poor fuel mileage and potential catalytic converter damage.

Thermostat stuck closed: If the thermostat is stuck closed it will restrict flow into the engine resulting in an overheating condition, resulting in potential catastrophic engine damage.

About Genuine Land Rover

The same parts Land Rover used to build your vehicle are sold as replacement parts under the “Genuine Land Rover” brand. These are manufactured under Land Rover’s direction, guaranteeing top quality. As you’d expect, they also carry a premium price and are sold exclusively through the Land Rover dealership network.

Genuine Land Rover parts trace their origins back to the earliest days of the brand in 1948, when Rover engineers built the first Series I using robust, serviceable components designed for durability in harsh environments. Over the decades, Land Rover established partnerships with leading European suppliers to ensure consistent quality and performance. This tradition continues today, with Genuine Land Rover parts representing the official replacement components engineered to the same specifications as those used on the production line.

What many owners don’t realize is that Land Rover doesn’t manufacture most of these parts themselves. Instead, they design the components, contract trusted suppliers to produce them, and then verify the quality. Many of these suppliers have partnered with Land Rover for decades. In the industry, they’re known as OEMs (Original Equipment Manufacturers)—brands you probably recognize, including Lemforder, ZF, Sachs, Bosch, Valeo, Zimmermann, Siemens VDO, Corteco, and more. It’s not unusual to open a Genuine Land Rover box and find one of these brands inside—just re-badged with a Land Rover logo.

On our site, look for OE tags on product pages to quickly spot parts that come straight from the original manufacturers. Choosing these can save you a significant amount compared to buying them in Genuine packaging. For more details on how to identify OE and OEM parts, check out our OE Academy.