heater / blower fan

shikzachaser · shikzachaser's Garage

My fan sounds like either bearings or something rubbing. How difficult is it to replace?

Thanks:

Steve

AFJuvat · 04-07-2007, 09:37 PM

THe one in the back is easy, the two up front are a bit of a pain, you need to remove the cover, then go between the squirrel cage and remove three screws to get the fan out.

04-09-2007, 09:35 AM

AFJuvat, the three screws, are you talking about the front fan motors? If so, where are the 3 screws, I've been looking to remove the right front fan and haven't seen them.

Thanks

AFJuvat · 04-09-2007, 10:08 AM

Yes, in the front fan motors.

They are located behind the squirrel cage. Spin the cage slowly and use a flashlight - you will see three black screws. Remove them and the motor should pop out.

Tall02 · 04-10-2007, 03:25 AM

If you are refering to the front heater ventilation fan then you will find this fan in the front firewall and it is more challenging to replace than the rear engine fan.

I am assuming this is a 964 . If so then the process is:

There are some descriptive processes in this forum. But just quickly under the front hood the top plastic cowel needs removing. The ductwork over the squirelcage fan needs to be removed, Clips hold the top half on. once the squirrelcage fan is exposed the fan must be turned to align the clearance holes to the screws on the inside of the fan. I believe these are tork screws. Do not drop them. Then two long screw drivers are require to be inserted into the spring clips to release the fan motor. This may take two people. One to press in on the clips and the other to slightly pull on the fan cage. If you purchase a new fan and squirel cage ahead of time you will be able to study how the motor is attached.

The driver side is harder to work on. Make sure you loosen the hose clamp so the air conditioner hose can be moved slightly for clearance.

Good luck

sixbanger · 04-17-2007, 03:44 PM

When you turn the thermostat up on these cars is the fan going to run or as you call for more heat will the fan shut off. Someone explain to me how it should operate.

Tall02 · 04-17-2007, 06:24 PM

There are climate control mixing chamber servo valves on the front firewall that mix the fresh air with the heated air from the engine. As you increase the temperature on the climate control the mixing chamber servo valve opens on both the left and right side. There are other sites in this forum that go deeper into troubleshooting the mixing control servo with photos.

Good luck

shikzachaser · shikzachaser's Garage

On mine the air blows fine on the coldest setting, w/ or w/o the A/C compressor turned on. As soon as the setting is moved past cold it shuts off. Previous to that the rear fan bearings were making noise. One other thing is that if I have the fan speed up and the temp set to hot the fan will blow for about 2 seconds upon startup then stop.

Thanks:

Steve

sixbanger · 04-18-2007, 05:43 AM

This fan is doing the same thing. On for a few then it turns off. The car's owner is telling me that it used to run on and now it won't. I read his owners manual so I see how the factory say's it should work. I think the fan has been broken for so long that he forgot how it works. I hope.

dependencies · 10-19-2007, 11:57 AM

Last Two posters....

Tell me,
did you make any progress on the fan, specifically making it blow HOT air

my car does precisely the same thing, and like One of you, the rear fan was indeed making a bearings' type noise not long back

thank you

sixbanger · 10-19-2007, 01:06 PM

Whats your problem with the fan? The rear fan is easy to replace.

dependencies · 10-19-2007, 01:13 PM

Well,

start engine,
switch on blower (ask for heat) 2 seconds blast.....

off it goes

turn down thermostat

blower comes on, well usually anyway

Having read through a mountain of threads here the last few days,

it appears not unknown for the back blower to have failed,
which apparently (and I suppose makes sense) has an affect,

on the intricate world of Porsche heating

after tis evening reading your experiences, got me thinking,
'well that rear motor has been ever so slightly squeaky just lately'

in fact I'm actually wondering when I last heard it screeching come to think of it

shikzachaser · shikzachaser's Garage

I hate to say it but I sold the car and the buyer did not care. I went to the dark side and bought an ML55 AMG w/ the 964 proceeds. What is even worse is that I had to either sell the 964 or my 944. I chose the 964, I am truly a dumb ass or else I have great sentimental attachment to the 944.

Steve

dependencies · 10-19-2007, 01:49 PM

Oh well worth a question

good luck

sixbanger · 10-20-2007, 07:10 AM

After reading about how the heater works I found that it will not operate in warm weather. So I think it will need to be taken to cold storage area such as maybe some under ground storage where it is cooler and give it a test then. Or wait for winter to arrive to test it. It won't come on in hot air, it's just the way Porsche made. GOOD LUCK

sixbanger · 10-20-2007, 07:14 AM

Also my heater does just what your's does. It comes on then goes off. They didn't make many 964's so it's hard to find information on the heater You might try to put a window air conditoner in your garage window and let it cool down then put a hose on the exhuast out the door and try to operate the heater and see if will work. Just a thought.

dependencies · 09:17 AM

Well I bought the car in Summer,
And now I come to use it pre-Winter mornings I can safely say it doesn't blow hot air when stationary at least,

Pulled the rear blower off the car and ran it. Off a battery this morning, and it works fine.

I noticed early this morning when driving it though, that turning temp down by half prompted blower into action OK

Well I've had an SC the last 5 years, so I'm intimately familliar with Porsche's Teutonic approach to comfort,
it seems another slight payback, to otherwise brilliant performance.

That aside, I'm slightly suprised at reticence of the members replying,
(apart from you Two of course)

Thanks for your help
It IS appreciated believe me

Richard
UK

sixbanger · 10-21-2007, 07:18 AM

You need to find a shop that has worked on a lot of these cars as the average person only knows what they have delt with as far a the heating system in these cars. They will better understand how the system works as they will have worked on many where the rest of us have only worked on one.

dependencies · 10-21-2007, 08:52 AM

I've a theory on its behaviour actually now I've spent some time poking abouts its components,

Today has again been cold outside,
and using it this morning it only appears to blow at all with temp turned down by about half generally,
it makes me think the dashboard sensor tells it the cabin is say 30o and blowing cold air in with the engine not warmed up on start up, would actually lower the cab temp, so don't blow

given a choice of less-than-perfect heating, and a large bill to replace a control unit on spec'

I'd rather spend the money on the Engine/Tyres first

I'll buy a coat if it comes to it

bigchillcar · bigchillcar's Garage

where to begin with my 964's peculiar 'climate control'...'teutonic' may actually be a generous description...

my cabin air blower tends to blow its 25-amp fuse every few weeks with much use, so i'm assuming it's going to fail soon...drawing too many amps and eventually melts fuse..

also, the temp control works..but god only knows what it uses for making decisions. if i select hot, i may get hot..it may stay cool air. it may roast my balls off on a relatively 'cool' setting. i'm guessing at that point full temp would cook a turkey inside the car. obviously, my mixing valves are having problems as well as the blower (read: '$$$'). i can hardly wait to see where all this leads this winter, as i have little control over what it does. sometimes the fan runs when it's turned off..or not at the proper setting..then it changes as i drive.

my ccu is clearly possessed..