Odd Fiesta ST heater thing

[LuS1fer]

I was at the lights this morning and the Fiesta is always notable for being able to blow hot air on your foot even when screen demist is selected which I have always assumed is normal.

This morning, after a few minutes, it all went cold and I thought "Goddammit, here comes winter problem one" but on driving away, it slowly resorted to blowing warm again. Air con was on though that shouldn't make any difference.

It didn't seem to do it again but I was just wondering whether this is symptomatic of something about to fail. How does the heater mechanism work on these (I'd have a look but it's dark and lashing down).

Cheers.

[LuS1fer]

This turned out to be the header tank needing topping up, nothing more - a corollary from its removal trying to get at a sidelight bulb in the autumn.