[s-cars] cooling problem and question

[Tom Green]

> 2bro whilst digging up wallet asked-
>
> "i bought the thermostat and need to install it now.  The dealer told 
> me
> it would take 6 hours and cost arond $1000 because you need to get past
> the timing belt and water pump.  is this true?  how hard is it to
> replace?  can I do it in my garage?  Thanks"

>
> 2bro
>
> Six hours?  Don't think so.  It's a little hard to get to but its not
> where they say.  Should take no more than an hour once you gather your
> tools.  Search the archives as I'm sure there is some BTDT's.
>
> Be smarter than me and drain the coolant first and have new coolant on
> hand (or reuse old if caught in a clean bucket.) Position new 
> thermostat
> with the metal bridge part perpendicular.
>
> There ya go.  Put $500 in the bank for yourself and send me the rest;)
>
> HTH
>
> Bill m

As usual, Bill Mahoney dispenses sound advice.  He really means 
vertical on the bridge.  The Bentley repair manual can be had for less 
than $100 on CD and contains a wealth of information including detailed 
instructions for changing the thermostat.  If you just got this car 
('94 S4 ?) and have any doubts about the coolant, I would flush and 
fill with new Pentosin coolant.  If you use pink, just be sure to 
thoroughly flush the green or blue out or it forms sludge when combined 
with pink.
The thermostat is in a gooseneck fitting where the upper hose comes off 
the front of the block.  The bolts require a u-joint socket extention  
or you won't be able to use a socket wrench.  The thermostat has an O 
ring seal.  Notice when you remove the old one so you don't put it in 
backwards.   The gooseneck is probably thermoplastic of some sort, so 
don't overtorque the bolts and break it.  If your hose condition 
supports that expensive new coolant, check the clamps and refill.  
Oldtimers would like to get the coolant filled to the thermostat level 
before closing up so you don't have an air lock that prevents the 
coolant circulation and resulting hot water to the thermostat.  Then 
recheck the level after first shutdown.  HTH

Tom '95 S6