Changing fan belt

I know these are really naive questions, but ...
Started up the Carrera to drive to work this AM and noticed the alternator warning light on and found the fan belt broken. A quick look at Bentley and noted that it says you need a special tool to hold the fan pulley still while removing the bolt. Do I really need this special tool?
My 17 year old son was driving the car yesterday and I wonder if the engine might have been damaged if the fan belt was broken while he was driving. I know VW type 1 engines heat up very quickly when the fan belt breaks.

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John C
1988 Carerra coupe
1957 Speedster replica
1997 A6 Avant

You probably don't need that tool specifically, but it helps. You need a way to hold the fan still while you loosen the nut.
Replacing the belt is easy, but the KEY is that you need to use ALL THE SHIMS. There should be 6 or seven. The belt is adjusted by putting the shims on the inside or outside of the fan (more on the inside to loosen the belt, more on the outside to tighten). But, they all must be there. You won't get the belt to tighten right if you don't do this, and will ruin the fan.
And, yes, this is like a Type I in that the engine will overheat and damage VERY quickly after the fan belt breaks.

John,
All the tools you need should be part of the tool kit that comes with the car. It should be in the trunk, and the 2 tools you need are the one that looks like a lug wrench (for the fan pulley nut), and flattened rod looking thing with a half circle at one end, with a little 'nipple' that fits into a hole in the fan pulley to allow you to hold it still while undoing the pulley nut.
Also, see if you can find out how long the car was driven without the fan belt working!
Good luck!
Craig

Squeezing the fan belt on one side may give you enough purchase to break the fan pulley nut loose with a long breaker bar. It's easy to tell which side will hold against the unloosening force.
The wrench is the easiest but those tool kits don't always remain intact and complete.
The shim advice above is indeed critical.

John:
Here's a link to the Pelican Parts technical article on replacing the fan belt:

http://www.pelicanparts.com/techarticles/911_fan_belt/911_fan_belt.htm


If you don't have the wrench to hold the pulley, DO NOT do anything dumb to damage the impeller (like put a wrench in one of the blades to keep it from turning). If you break the fan, you've had it.
I see you've got two Porsches. One or the other's toolkit must have the funny looking spanner to hold the fan pully from turning.
You'll need a pipe to fit over a wrench to get the fan nut off (for extra leverage). They're usually really tight.
Let's hope the boy didn't burn things up for you.
regards,
jlex.

The car will easily overheat without the fan working to keep it cool. Lets hope your son wasn't running up the RPM's, or driving for long in stop and go traffic.

Nick.

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_ _ __ _ _
Nick Shumaker
1982 911SC Coupe
nickshu@yahoo.com

Thank you so much, everyone. That is all very helpful. Unfortunately my miscreant son says he never noticed a red light on, so I have no way of knowing if the belt broke when I started the engine or whether it was broken for part of the time he was driving.
Now for the next question ...
When I get the new belt on, what signs should I look for to tell if the engine has suffered any damage from overheating?

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John C
1988 Carerra coupe
1957 Speedster replica
1997 A6 Avant

smoking and knocking would be a couple of things. if it has good oil pressure and it's quiet,and still runs well, you got lucky.

smoking and knocking would be a couple of things. if it has good oil pressure and it's quiet,and still runs well, you got lucky.

Just in case your tool kit does not include the spanner needed to hold the fan in place, I believe a bottom bracket tool (for a bicycle) is the same size... and a lot cheaper. It's too cold to go out in the snow and check my BB tool against the P-car tool, but I believe they are the same size.
Anyone care to comment?


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Dan Tolley
1987 911 Coupe

Why is it critical to put the "unused" shims--i.e. the ones that aren't in place between the pulley halves--back on the alternator shaft between the outside of the pulley and the bowl-shaped washer under the big nut? I ask this because my shaft is slightly shorter than it should be, after an alternator shop fixed the threads stripped by the PO, and if I leave the "unused" shims off and put them in the toolkit, say, I get another thread or so for the nut to grip. It seems to me that storing the unused shims on the outside of the pulley is merely convenient but not necessary. Is there a flaw in my reasoning?

stephan

Stephan,
On an original, unmodified shaft, all of the shims are required so that the pully nut will not reach the end of the threads on the shaft before tightening against the stack of shims and the pulley. If more than two or three shims are left out of the stack then the nut will contact the unthreaded portion of the shaft before contacting the pulley/shims. This is a common cause of stripping the nut/shaft.


-Mark
70 911E

Hello

Just to mention the newer shafts have a 8mm Allen head integratet so you don´´t need the spanner. The shaft center is normaly covered then with an black plastic hat.

Porsches have different alternators / toolsetcombos 356 and beetle are 36 mm Nuts.

Grüsse