Advice/help required with a coolant loss/temp issue
 

My MY98 WRX has been losing water over the past couple of weeks. Its about a half litre a week, couple that with the water in the footwell and it looks like a heater matrix leak.

However, after bypassing the heater matrix the car seems to have stopped leaking water, but now the normal running temp is only 83-84c whereas before it was 86-87c.

So, I have changed the thermostat and this has made little difference. But this gets me thinking about the sensor that feeds the temp reading to the ECU. If this is faulty then the car is probably running at the correct temp but the ECU isnt seeing this. Also, the rad fans kick in at 91c, which may not actually be 91c IF the sensor is reporting the temp incorrectly. If this is the case then I may be overheating and either venting water off as its too hot or overpressuring the system causing a leak?

What do people think?

Is £30 about right for the sensor?

Cheers,

Wayne.