OT: Vauxhall Air Blend Heater

Budget model Corsas I know about have air con. One still working well after 8 years no maint, another, same vintage, not working at all due to leakage, presumably from a prang (one not careful woman driver), £300 quote to fix.

All car heaters are air-blending, surely. They have been for years.

My Mk 1 Escort sent the cold air above the dashboard - the same vents used for defrosting - and the hot air to your feet. Usually good, as the cold air kept you awake, but a bit uncomfortable in very cold weather. I think models sent to very cold countries controlled the flow of hot water through the heater core.

and very quick to leak ....

Before that, the ones which just had a matrix and fan, with no outdoor air flow - would be simply controlled by whether you turned the fan on or not. If was still too warm, even with the fan off, then there was a valve under the bonnet to turn the heated water off.

One car I had, Ventura, had an early automatic incoming air temperature control. A mercury bulb measured the temperature, expansion and contraction adjusted the temperature of the water, depending on how you set a dash control. Very clever for it's day.