SERIES 3 Heater blower question.

Hi all. Hope you are all keeping well in these most difficult times.....I have a question about my heater blower unit. With the 2 stage switch, it blows from very slowly to slowly. I'm sure it's working as designed but it's pathetic compared to the blast from my other halves Renault Megane heater. My question is, is the blower controlled by a resistor like modern cars, or is it just a direct feed from the switch. I was thinking of getting a modern blower unit and fabricating a housing that suits the series 3 mounting application but I just wanted to know the deal with the resistor if there is one. I know a defender blower is probably the popular upgrade but I wanted to try and make my own if the series blower is just really poor.

Thanks people....

First get the fan working as it should; clean all the connections, oil the motor and clean the matrix out. Then if its still pants you can fit a modern fan but don't do this until the wiring is tip-top as the modern fan gets its power from drawing more current and if the loom can't power the one you have now it certainly wont power a bigger one. The 2 speed is resisters, on modern fans these are often built in with a heat sink.

rob1miles said:

First get the fan working as it should; clean all the connections, oil the motor and clean the matrix out. Then if its still pants you can fit a modern fan but don't do this until the wiring is tip-top as the modern fan gets its power from drawing more current and if the loom can't power the one you have now it certainly wont power a bigger one. The 2 speed is resisters, on modern fans these are often built in with a heat sink.

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Cheers.....Thanks for that. Some very helpful information there

On my S3, the resistor for 'low' speed is a small coil of resistance wire, mounted in the top of the heater matrix box, just inside the air inlet. Not a bad idea, and it ensures there's a flow of air over the coil to cool it, when the fan is on...

TheMegaMan said:

On my S3, the resistor for 'low' speed is a small coil of resistance wire, mounted in the top of the heater matrix box, just inside the air inlet. Not a bad idea, and it ensures there's a flow of air over the coil to cool it, when the fan is on...

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Thats interesting. I must look for it on my setup. A previous owner did the double up mod on my matrix and it makes a huge difference in heat output. The problem is it just doesn't come out fast enough with the crappy blower. I've seen a few old posts on here recommending an ebay 4" bilge blower connected inline after the standard blower although I couldn't find any comments stating how effective they are but they do appear to have a good flow around 240 cf per minute if I recall correctly. If this is true, it would be a vast improvement on the original.

Someone on here determined that when in motion, the air inlet on the side of an S3 is actually in a low pressure area, so the fan is sucking from a partial vacuum. Their solution was to run some ducting down to the front of the vehicle (inside the engine bay!) and T it into the supply from the fan, so you got a ram air effect when moving forwards. There was a thread about it several months ago.

Your biggest loss is likely to be poor connections with a high resistance and dry motor bearings. Once those are sorted it may be OK. These cost nothing so they are a good place to start.

I tried a bilge blower on mine but I bypassed the ordinal motor so it wasn't down stream of the old heater motor. It certainly sounded a lot faster than the original but it didn't seem to make much difference to the output at the vents. It was all a bit Heath Robinson as I was only experimenting with improving the airflow rather than the heat. My experiments were with the landy stationary. I wanted a flow of cool air for summer driving rather than heat for the winter. I abandoned the effort and bought a fan for inside the cab. I've seen some posts about stripping the matrix box and fitting better insulation which is something I might try at some point but the bilge motor has been cast aside. The trouble with series landrovers is that they are a big uninsulated tin can and even if you fitted a system off a modern vehicle, it would still struggle

Col

I have a double matrix on my series 3 swb mended the holes in fan casing and it works ok . I made this fan with an LDV van fan unit but still on the shelf in my garage as system works at the moment.

One of the problems is the dash itself. When all is working well the air still has to go through an assault coarse before finally arriving at either the footwell vents or demisters. Its not a great system for a drafty old vehicle. Mine does all right in reasonable weather but was lacking in the winter department hence the addition of a diesel heater under the passenger seat.

Blackburn said:

I have a double matrix on my series 3 swb mended the holes in fan casing and it works ok . I made this fan with an LDV van fan unit but still on the shelf in my garage as system works at the moment.

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Wow....Well done. Looks like a serious improvement to the original. Would you wire it direct through a relay to the original 2 stage switch or would you use a resistor setup with say a 4 stage switch for serious airflow when required?

I have fitted a 3 stage switch in preperation for change over.The resistors are the original ones from the LDV inserted on opposite side of casing to the photo in the same way as the LDV fan casing had them.