One of the things that is highly recommended for all new ZT owners of any model is to check that the plenum drain is not blocked.
First thing I had to find out was “what is and where is the plenum!!” Well it’s that chamber that sits between the engine compartment and cockpit – usually the section below the windscreen with all the vents in it.
I followed a YouTube how to remove the vents and look inside the plenum chamber …. Search for “plenum drain mg zt”.
When i found the drain it was clear and the whole area clear of rubbish/leaves etc. I poked a stiff wire down the whole to check it was not blocked. I have circled the drain and the exit pipe in the pictures.
There’s also a similar drain on the other side but not as easily visible. The drain tube exit can be seen in a similar position on the other side. It may be easier to poke something up it from beneath to check it is clear.
Ideally you need to find a way to prevent leaves and debris finding there way into the plenum chamber in the first place.