The heater fan box is something that may be missed during a restoration, however I thought it would be best to strip it down and inspect. The foam gaskets were all completely perished so this would have affected the directional airflow.
Now luckily this task does not require a huge amount of costly replacement items, I could have bought a new bmw heater valve and matrix but I decided against this.
It does seem like a daunting task from the outside however it is quite simple once you get stuck in, especially with mine being a non aircon variant.
Parts used:
Heater Matrix - www.ebay.co.uk/itm/145086729266
Adhesive backed foam - www.ebay.co.uk/itm/1446473916...
Harness tape - www.ebay.co.uk/itm/165498029293
BMW gasket - 64111370937
BMW gasket - 64111370936
BMW heater pipe o-rings x2 - 64118377824
Time Codes:
0:00 - Intro
0:36 - Disassembley
5:49 - Foam Replacement
12:23 - Heater Valve Reseal
15:37 - Wiring Loom Taping
16:29 - Reassembly
22:34 - Outro