With the weather getting colder my '86 cars heater has very little puff so I decided to have a go at it. Removed the fan and measured from the housing to the fan flange and compared to the measurement from the motor flange to the blade and found there's a gap of about 5mm between them which allows the air to circulate, the closer they are the better. It's also noisy so I dismantled the motor and put a little splash of thin oil on the bush. Put it all back together and put the blade back on a little proud. Offered it up and it was catching, pushed further on in small stages until it was running free. Closed it all up and it's not as good as a modern fan but it's quieter and there certainly seems to be more air. If this doesn't do the trick I may try modifying the lip of the housing so it goes outside the fan blade. Plan B could be to get a replacement heater unit with modern fans.
There may be photos below if it works!
Heater Matrix Fan Simon :santa2:
