If the slight clicking noise is what you suspect to be the fan in your earlier post. Have another look. It may be the internal distribution valve for the heating. Mine does it and took me a while to work out what the noise was.
Its the unit that changes the flow of air and heat. I had it go on my ZS180. Haven't got round to fixing it as it didn't worry me too much.
1958 Ford Consul Convertible
1965 Ford Zodiac Executive, being restored
1997 Jaguar XK8 Convertible
2003 Number 182 MGZT V8
2004 MGZT cdti Poseidon
2004 Number 76 MGZT V8
Its the unit that changes the flow of air and heat. I had it go on my ZS180. Haven't got round to fixing it as it didn't worry me too much.
Think you will find it controls water not air.
ZT 260's are different to the V6 ZT in the way distribution works, and I assume the ZS.
Rover 75V8's are different again which is why the "Y"-piece fix doesn't.