I dont have a water level guage on mine, just temp, rest is done by the display beneath the clocks, but I have just had cooling system problems, rather disasterous ones!
Are you finding that even when the car has been left overnight, when you remove the radiator cap you get a big inrush of air?
Are you getting air locks?, car at normal temp, heater not as warm as it should be?
Does the coolant get hot for no apparent reason?, eg, youve just done a run down the motorway, stopped in a layby to get something out of the boot and the coolant is too hot (warnings on display below clocks)?
I thought my problems has only started after I had removed the radiator cap and water escaped, I thought I hadnt let it cool down enough, but unfortunately that wasnt the case, my mechanic tells me the antifreeze has eaten the head, the other thing I noticed was the pipes to the radiator were "rock hard" when the engine was running, I now know this was due to number 2 & 3 cylinders pumping up the water system!
In the latter stages of faliure, when started from cold it would appear to be only firing on 5 instead of six, a quick blip of the accelerator would soon solve this, but it is now obvious it was water in the cylinder.
I hope none of this is true for you, I'm told the older cars are vunerable to this sort of damage, as antifreeze wasnt as advanced "then" as it is now, even being called coolant now.
Good luck