Heater matrix leaking????????

[66split]

Hi, my girlfriend is currently driving a mk1 1100 which has started to run a bit hot and loses 2 litres of water every 30 miles or so. I have done a compression test, leakage test changed thermostat.  I am pretty certain the head gasket is ok (i put a new one in 6000 miles ago) Now the passenger footwell is full of water. Could this be coming from the heater matrix, are they prone to leaks. oh yeah theres no water in the oil either or in th exhaust.  If you reckon this is the problem how much of a sod is it to replace. ive got a sneaky suspicion it lives behind the dash???
Any ideas
cheers folks
66split

[richandhazel]

Probably is the matrix, not that uncommon. I don't think its too bad to change on the 1100.  If I remember correctly there is a plastic cap over it.  I don't think its necessary to remove the whole heater assembly to change it.