I have a 2000 model Peugeot 306 2.0l hdi.\nRecently I got in the car and there was a good inch or two of water in the driver's footwell. I found the cause for it and have cleared it and managed to dry out the carpet, however since then the engine coolant level warning light has come on- weirdly it's only illuminated when the engine is off and the key is out of the ignition. When I turn the ignition on the light goes off(?!). This has meant disconnecting the battery every time I park up for any length of time. I have read elsewhere it could be trying to tell me that the sensor is on its way out. I have replaced the sensor but the problem has not gone away. If anyone has any insights on what my next move should be please get in touch.\nThanks in advance.