Main Hot Air Blower Query

[Lévon]

Can anyone please tell me the purpose / benefits of having the main hot air blower at the back of the engine compartment?
This has never worked in my car since I've had it, however air from the main engine air cooling fan is still able to be forced up through this blower and then round into the heat exchangers resulting in a pretty good hot air supply to the car when I need it, which can be further boosted by the fresh air blower in the front dash.
Should I try to to fix this main blower, or have others experienced the same and not bothered.

 

[dij999]

Does air from the cooling (fan-belt driven) fan really flow to the hot air blower ducting and then to the heat exchangers in significant amounts to provide cabin heating
in the absence of the electric fan?

Had an SC for 30 years and am surprised at that. Have replaced that blower once in the SCs lifetime but had its fuse blow more than once in that time.

 

[Lévon]

Surprising, but yes! The temp controls and springs have rusted, so I have manually turned one heat exchanger to on, the other one off. Nevertheless, the temperature inside the cabin is surprisingly warm in winter.
I want to get it fixed though - how easy was it to replace the electric fan?

 

[chris.hevey]

I'm not too sure about these things, but as I understand it the only purpose of the blower driven off the main belt system is to blow fresh air into the exhaust as it leaves the engine to fool the 1980s California emmissions tests. The car still creates the same amount of pollution, but this just diliutes the gas but by adding a slight extra load on the engine, thereby actually creating more pollution for no purpose. If you still have one of these it is your green duty to get rid of it and get a few HP more into the bargain.

This is mine with the parasite removed. You should be able to see the hole bottom left where the old pipe work used to feed through to the exhaust back box....

 

[T911UK]

Thats the air pump Chris, as you say to water down the emission results for California. The electric heater blower fan is mounted higher up above the air pump.

 

[Lévon]

That's right - it's not the "Californian parasite" which you are referring to - but the electric heater blower fan situated at the back on the left just below the rear windscreen motor.
Anyhow - Phil's response confirms what I thought that I probably don't need it. but will check out the fuse first.
Thanks chaps.
Lévon

 

[adriandavidson]

The purpose of the electric fan in the engine bay is to assist the flow of hot air from the engine to the front mounted air distribution box. This box also has a fan and various flaps to control the flow of air and also to allow hot and cold air to mix to allow for temperature control. The 2 cable controlled flaps in the engine bay each side of the gearbox should be lubricated once a year and you should operate them at least once every time you drive the car to prevent the seizing up. If you have the centre consul mounted automatic temperature control set this to the hottest setting for a couple of minutes and then to the coldest, this should move the flaps and prevent them seizing.
To answer the original question, the electric fan in the engine bay is make the heating system more efficient, or at least work.