Bit of a weird one...?
I had a small leak in the water hose that runs to the heater core. I found this as the "low water" light came on...EF Fairmont Ghia btw.
I flushed out the water system and refilled etc...
Now the "low water" light doesnt seem to want to go off. I woud normally assume the float has busted or crumbled due to age, just like me EA did. BUT, the light doesnt come on with the ignition, and only comes on about 30 seconds after starting the engine. Wouldnt it come on straight away if it was a fault with the float or sensor. The water level is DEFINATELY ok. ANy ideas? IS it just a knackered float/sensor?