[s-cars] coolant loss

[Tom Green]

> Riff ponders:

> How much coolant should I drain before changing the t-stat???  I'd 
> rather
> not do an entire flush and fill if it is not needed?  I think I will 
> try to
> tackle this one tonight in my freezing garage....
Paul K offers sage advice:
> My technical answer is 'some', and I'm sticking to it.  Dunno, it was 
> more
> than a little though.  Like have a fresh bottle of G11 laying around 
> and be
> ready to use a good amount of it.  Maybe start by draining say 1/2 
> gallon
> and then try cracking the hose off the tstat housing and see if it 
> splurges.
> Repeat if necessary.  Oh, haven't heard anyone mention letting the 
> system
> 'burp' when done, I didn't enough when I did my radiator and it kept 
> purging
> air (well, air purged COOLANT, $ coolant at that) out a few paths of 
> least
> resistance.

Now, Mike must ask:

> After draining the system how do you fill it back up?  I went to do the
> t-stat replacement over the weekend as as advised by many listers but 
> realized that
> there was no radiator cap on the s-car and my friend was unsure of how 
> to
> fill it and burp the system once finished.  do we re-fill from the 
> expansion
> reservoir and leave the cap open until the t-stat opens?  also, the 
> vw/audi green
> coolant is the right stuff, correct?

Sorry, Paul, that's a sorry answer.  Riff, drain enough to cover the 
entire garage floor with a thin, slippery layer (since it is almost 
impossible to catch all that will drain out).  Especially if you use 
Pauls garage.   Then lay in it to close the radiator drain petcock.  
Mike, out the bottom and in the top (expansion tank) .  I would cap it  
after trying to get as much coolant in the system. You just want to 
avoid operating the engine after it warms up without coolant flow. If 
you have to run to work before the air is purged, take some coolant 
with you to top off before heading home.   I have not seen any Autobahn 
or VAG coolant I would classify as green.  Certaintly not old 
antifreeze green.   The interest in Pentosin blue, pink , or purple or 
VAG or Autobahn pink or straw color is knowing what  is in your system, 
because not long ago Audi radiators were only available from the dealer 
at many $$, and had fittings and gaskets that the old green stuff ate 
for lunch and clogged the core of the non-repairable part.
Enough talk, just do it guys.

Tom '95 S6