aircooledbug

On the way back from a friend's house last night I turned on my heater fan to discover it will only work for a few seconds before cutting out. Turn it off and on again to get the same result.

A quick search points me towards possibly a blown fuse which if so is probably caused by the blower unit being at or near end of life - motor, bearings or something. It looks like an easy DIY swap out with the only pain being the usual Porsche parts availability and pricing madness. Apparently the 964 part is no longer made and I will need to make some Heath Robinson amendments to fit a 993 version, which is not really much of an issue.

However, I did see mention of an RS style rear blower delete with reference to someone using one in the Netherlands who still found the heater to be sufficient. Saves some weight, clears some space in the engine bay and removes the chances of the problem reoccuring. Has anyone here done it who can point me in the right direction as to how to do it, what parts I will need and where I can buy them?

Aside from this, my front blower fan on the driver side is squeaking (as per my thread last week), it seems like they are all ready to die together. Given this should I be investing in a motor removal tool (no idea what it is called, looks like a three pronged extraction thing?) and replacing just the motors on both?

Garage is not heated so really need some spring weather to come fast.

Rocket Rob

Swapping out the rear heater blower is very easy. Don't worry about the 964 vs 993 part number differences. If you move the bolt spacers from your 964 blower to the 993, it will fit perfectly. Do you have Andrian's book? It outlines the change well. The 964 spacers are 6 mm shorter than the 993 ones.

Sorry, haven't changed to the RS delete but many others have.

ToreB

My DIY web page describe how to test the rear fan, it might just be a problem with the low speed resistor. (it has a bimetallic switch that might fail over time)
Have a look here to see the details: www.porschehvac.bergvill.com
Cheers,
Tore

cptnzero

If it is the motor and you do not want to go down the RS route then you can just replace the motor instead of the whole assembly. I bought one from a german website last year and I think it was in the region of £110 including shipping. type11 also has some

http://www.type911shop.co.uk/shop/ar...26aid%3D851%26

aircooledbug

Rob, tore, cptnzero...

Thanks. Some good tips/advise there. What is 'Adrian's book'?

Rocket Rob

This is Adrian's book. I highly recommend it.


http://www.bentleypublishers.com/por...companion.html

cptnzero

There are some instructions here for replacing the motor, a very easy DIY.

https://rennlist.com/forums/964-foru...wer-motor.html

aircooledbug

Thanks.

The more I dig into this, the more I am wanting to rip out the whole rear fan and put the RS part on even though it appears that replacing the fan motor is the cheapest way to solve my problem (providing it is not a fuse or low-speed resistor). Unless I am being very stupid, the way I understand there will still be adequate heat in the cabin, all the blowers destinations (windscreen, dash and footwell) will still work perfectly well except for maybe some loss of capacity at idle speeds.

Who has already done it? The engine bay looks better without. Tempted to run some ducting in place of it!

Babalouie

I've done the heater bypass, with the RS tube. And I would say that there really isn't any noticeable loss of heat or volume of air. Mind you, I do live in Sydney and so even in winter, two clicks on the fanspeed dial is enough for me, and I haven't found that I need to "turn it up" more than when the blower was working.

The factory part number should be easy enough to find, and in addition to removing the blower, you also need to do a wiring mod, which is very quick and easy and can be found here:
https://rennlist.com/forums/8964599-post79.html

The other end of the wire, goes to the +ve low tension post on the coil, is needed to fool the CCU into thinking that the blower is still hooked up. And there is no battery drain with this mod

aircooledbug

Thanks for the confirmation. I think that's where I am going to go with it

dkcaims

Colorado had some below zero nights a couple weeks ago and I took the c4 out when it was about 5 below zero. With fan delete and RS bypass, once warmed up I had to turn down the temp to mid range, it was that warm in the car.

ToreB

Be aware, the rear fan has two functions, to help pushing heated air to the cabin, and to cool the engine at ignition off. A rear fan delete would do away with the heat exchanger cooling function. Personally, I would not do this if I'd be using the car in hot conditions.
Details are given here: www.porschehvac.bergvill.com
Cheers,
Tore

aircooledbug

Good to know it will be warm - I don't think London get's anywhere near as cold as where you both live! Today is pretty grim though and a real hardship enduring walking over London Bridge to a meeting earlier at a Baltic 2ºC.

Personally, I doubt that the fan will add much cooling to the engine. About the same level of change as the performance gain from weight reduction without it.

aircooledbug

Finally got my RS pipe in yesterday and now need to sort out the wiring so the front blowers work.

Are there anymore photographs for this so I can identify where the wire is that I need to add the fuse to and plug into the relay pin socket?

Managed to work out that fuse/relay box is on the left in the engine bay - that tells you the level I am at.

circleswim

I believe this link will give you the info your looking for...

https://rennlist.com/forums/964-foru...ss-tube-3.html