Supernaut's Cars - E36 323i / mk3 Megane / S1 Land Rover

[Tayne]

Does your one have a hedgehog?

[Supernaut]

Not that I'm aware.

It has this style of climate control:

It seems that the fan (I've tested it and it works) blows into an air temperature sensor built into the unit. Hmmmm.

[SiBriers]

Not sure the hedgehog would explain that behaviour (that's usually certain fan speeds not working or the speed wandering).
On E46s, the top centre fan outlet has a heat control - without air con this could be as you describe - ambient air until the thermostat opens and hot coolant reaches the heater matrix.
Also possible that the heater control valve (on the passenger front inside shock tower on E46) has locked up or is getting stuck - supposed to blend the amount of engine coolant the heater matrix sees.

[Supernaut]

I think it's actually just behaving as intended.

I set it to 16.5 this morning and it blasted me in the face with maximum heat... for a couple of minutes before calming down a bit. It's just a bit much with the dashboard vents right in front of my face in such a small car!

I also changed the oil today as it's that time of year. It's only done 4k miles in the past year though.

Oh yeah, it crested 190k miles a couple of hundred miles ago.