I was driving into town today with the fan on at 1 when I felt the cabin becoming usually warm - the temperature dial was set around 20 degrees - it was a cold/mild day (9 degrees) so I turned down the heat dial to minimum. Later on having parked and returned to the vehicle after 20 minutes, I went to drive home and felt cold so I turned up the heat dial to midway and just cold air was blowing through. Having then set it to Max heat, only cold air remained to flow into the cabin.
I have read previous forums on this issue - I have checked the antifreeze coolant level which remains at Full so this suggests there is no coolant leak and the cabin floor is dry with no obvious sign of any leaks. Its been absolutely fine until today.
What was unusual was that sudden burst of heat like opening the car door into a hot summers day feeling then later on no heat at all.
Any thoughts on this?
Many thanks