Mod Details

PremiumYes Difficulty Mod ID1226 CreditPeter G For Linkhttps://www.evilution.co.uk/mod/roadster-thermostat-valve-change.htm Copy to Clipboard

What Are The Symptoms Of A Failed Thermostatic Valve?

The thermostatic valve starts closed which only allows the the water to circulate around the engine. As the engine temperature increases, the water temperature also increases. This causes the valve to slowly oen, allowing more of the hot water to flow to the front of the car and through the radiator.

Eventually, at about 85°C, the thermostatic valve is fully open which routes the majority of the water to the front of the car and through the radiator. This cools the water down to regulate the temperature of the engine.

The valve is designed to fail in the fully open position. What you will notice is that the engine doesn’t get up to full operating temperature and you’ll have almost no heating in the cabin. The other, less likely, alternative is that the valve sticks closed and the engine has no way to cool itself. This normally means full temperature in 5 minutes followed by a warning noise from the speedo and then a warped engine head if you ignore it.

Changing The Thermostatic Valve

The valve sits on the top of the engine just behind the fuel pressure regulator. Actually getting to it is tricky so you might want to lower the engine to make more room.

On top of the thermostatic valve is the coolant temperature sensor. Disconnect the electrical connection. Disconnect or move any other pipes/hoses that might be in the way such as the top engine breather hose.

Credit

Thanks to Peter G for most of the photographs.
Thanks to Tim for the info about the Click-R pliers.