The water tank in an N reg corsa needs filling regularly and seems to be getting worse?

Neil, November 2011

I have changed the coolant twice, there has been passages of time where there has been water under the car, but not all of the time. One of the signals has been lack of heating in the car when water running low, but recently engine overheating on a short journey?

Neil, November 2011

I assume you mean your coolant reservoir, not your screen-wash bottle.

You either have a leak, an airlock, or maybe the thermostat or the head gasket is on the way out.

Is it overheating at all?

Are there any signs of liquid on the ground under the car after it has been parked for a while.

Any smells of damp, or damp mats, inside the car (the heater matrix could be leaking).

Is the heater working properly?

When was the coolant last flushed out and renewed?

ChicksFan, November 2011

you have either a leak in the cooling.rad/hoses,thermostat housing/waterpump/.check all including radiator bottom hose,if all ok then it sounds like head gasket failure .check your engine oil for any signs of water .remove engine oil filler cap and inspect for white milky residue,.

mech monster, November 2011