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Fw: Performance Cooling Solutions




-----Original Message-----
From: Marc Getty <marc@getty.net>
To: Roland Johansson <scirocco@mail.bip.net>; scirocco-l@scirocco.org
<scirocco-l@scirocco.org>
Date: Sunday, August 15, 1999 9:47 PM
Subject: Performance Cooling Solutions


>Roland Johansson wrote:
>> If you use your motor "only" for racing/rally you can remove the
thermostat
>> completly and use a low temp switch.
>
>Being that I started the "Performance Cooling Questions" thread, I think
that
>it is only fair to post the results of my quest.
>
>First off, I believe the lines above by Roland Johansson above are
incorrect.
>The thermostat when completely removed from a Scirocco, just like my Jetta,
>will cause major problems. There are two paths through the engine, one that
>the coolant flows through when the thermostat is closed, the other when it
is
>open. Coolant is actually pumped through the engine when the thermostat is
>closed, but through a very short path, when the thermostat is open the
coolant
>is pumped throughout the entire system. If you remove the thermostat
entirely,
>most of it will take the path of least resistance and take a short path
>through the engine and not to the radiator. If I am incorrect about this,
>please let me know!
>
>Next, onto my "Performance Cooling Solutions". I have decided to:
>
>1. Remove the stock electric fan thermostat and replace it with a lower
>temperature thermostat purchased for $11 from Adirondack
>(http://www.germanautoparts.com/). My neighbor who has been a VW mechanic
for
>30+ years told me that the purchase of a lower temp thermostat is not
>necessary, he suggested that I clean out all of the gunk behind the
electric
>fan thermostat and all will be fine. I decided to both clean behind the
>thermostat (see #3) and while it's out I might as well replace the
thermostat.
>
>2. Leave the current stock radiator. The guy who answered the phone at
>Adirondack said that the radiator on my '87 16V is the same as used by the
>turbo diesels and that is as big as they get.
>
>3. Completely flush out the entire cooling system. This will include taking
>out the radiator and thermostat and pumping as much water through it as I
can.
>
>4. Use Prestone phosphate free anti-freeze (the orange stuff) as the
>replacement coolant. Phosphate free coolant is needed so that it does not
eat
>through my seals. I chose the orange prestone stuff because it was the only
>stuff in any of the three parts stores (Pep Boys, National, and an
independent
>guy) that I went to that actually said phosphate free on the label. I would
>have bought it from my local VW dealer, but their hours sucked and I could
not
>get there any time their parts department was open.
>
>That's it! This should help keep my Scirocco running cool for a little
while
>longer!
>
>-Marc
>
>'74 VW Thing - http://getty.net/thing/ FORSALE in Philly!
>'81 Jetta Diesel gone to the scrap heap after 178,000 miles
>'84 Jetta GLi SLC with only 164,275 miles
>'87 Scirocco 16V with 164,000 Miles, just got it on 7/2/99
>
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>
If you take the thermostat out totally, it will act the same as a stuck open
thermostat and not get warm at all.  Where I work, we would usually see this
in the fall since most people don't use their heaters in the summer,
customers who come in complaining that the heater isn't getting hot, and the
temp gage is reading between cold and 1/4, 99.9% of the time it is a stuck
open t-stat or someone has messed with their car and pulled the t-stat out
totally.

In my experiences, the 16v do run a little warmer than the 8v so most people
will install the 160 deg t-stat and either put the lower temp fan switch in
or swap the wires on the 2 speed switch and have the fans come on high at
the first stage.  I believe the 16v was made to run a little warmer than the
8v for performance reasons.  If the engine is noticeably different than it
has always been, then there is a problem and most of the time it is either a
leak (causing low coolant) or a stuck closed t-stat, or, a more uncommon
problem, but still a good possibility, a plugged radiator.  There is always
the possible head gasket leak, or fins corroded off of the waterpump, but
those take a little more diagnosing and usually take a while for the problem
to appear (gets a little hotter over time).  As far as the orange coolant
goes, I would stay away from it for a while.  Every newer vehicle that has
come into our shop we have had to totally flush because it seems to rust
MUCH faster than the green stuff.  I think it is still too new to be sure of
it's results in a cooling system.  Your best bet is to use distilled water
since it is pure water with no additives, no minerals, etc.  Minerals in
water, which normal tap water has, causes mineral deposits on the inside of
cooling systems and over time plugging components.  Once you do get your
cooling system operating optimally, flushing it once a year will usually
keep it good and rust, mineral, and gunk free.

Dave
Master tech
77 Rabbit 2.0L 16v


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