93 S4 viscous fan coupling

[john at westcoastgarage.net]

Ado Sigal wrote:

> All the viscous couplings on all clockwise turning engines are left 
> thread, for the shaft that is, so they can't get undone with engine 
> turning.
>
> HTH, Ado
>
>
> Bill Shaw wrote:
>
>> Don't know if it's the same,  but I just removed the fan on my '99 
>> a6qa in the process of doing the belt and it was a backward thread.  
>> You're talking about the one big nut,  not the little ones,  right?
>>
>> hth,
>>
>> Bill
>>
>>
>> john at westcoastgarage.net wrote:
>>
>> So I'm helping a friend do the T-belt on his '93 S4, and the viscous fan
>> coupling is resisting our efforts to dislodge it.  My V-fan coupling
>> experience is with BMWs and MBs, which use left hand threads to secure
>> the fan clutch to the hub.  Are Audis the same?  As always, all
>> knowledgeable replies are sincerely appreciated!  TIA, John
>>
>>
>> OK.  Again. Here's the answer we've all been awaiting.  Most (if not) 
>> all of you have given the same answer, and you're all wrong.  This 
>> last one gives the reason the bolt should be left hand thread, but 
>> the reason fails to account for the fact the pulley rotates in the 
>> REVERSE direction from the crankshaft, as it's driven by the BACK 
>> side of the belt.  Had I thought it out before blindly plunging into 
>> the familiar world of BMW fan clutches (had 2 of them off on 
>> Tuesday), I would have realized the answer and not posted the 
>> question.  As it turned out, soaking the nut with a few squirts of 
>> Kroil and letting it sit about 20 hours, repositioning the pin wrench 
>> so it was propped against the harmonic balancer, and giving the nut a 
>> bit of force in the correct direction with the big Stahlwille 32 mm 
>> long pattern wrench loosened it right up.  Switching to the thin 32 
>> mm 911 oil line wrench spun it right off.  Usually, they'll spin off 
>> with your fingertips, but this one had some corrosion inhibiting the 
>> free movement of the nut.  We've all learned something here, and I'll 
>> be sure to let you all know as soon as I figure out what it is!  LOL, 
>> John
>