T-stat change advice

[Matt twentyV]

Hi Bernie, yes the temps take forever to warm up.
Sunday morning 70mph steady on the freeway in 82F
ambient it dropped from 187 peak driving to the
freeway down to 182-183.  Can reach 190 in severe
stop/go.  The water and oil temp guages also suggest
temps are low (oil temp guage barely reaches first
hash mark above 60C, water 80C).  The T-stat was not
replaced when the 3B was installed (which was the
obvious time to replace it, doh).   So original
Tstat, and 3 sensors suggesting low temps.  MFTS
was replaced when the motor was swapped.  I'll put
money on the Tstat being at least partially stuck
open.  DFI only if certain that IAB.
I hadn't thought of moving the PS pump, silly as I
went that route when I replaced the radiator and
T-stat back with the 7A.  I'll look at it again
tonight.  BTW on that job I didn't remove the pump
just unbolted from the mounting and swung out of the
way.
I am trying to get everything perfect before
ratcheting up the boost chip.  For those that
remember, I originally was running very rich,
with low gas mileage (16-18).  New O2 sensor,
repaired wiring on IM temp sensor, and replaced ECU
code of unknown origin with stock, and now the engine
is running much better.  Block 000 channels 8 and 9
are right where they are supposed to be, and can see
23-24mpg at steady 70mph, though still 17 in heavy
stop-n-go traffic.  Only thing left that is not
perfect are the engine temps...

Matt

--- Bernie Benz <b.benz at charter.net> wrote:
> Hi Matt,
>
> What does the VC show as the warm up temp profile?
> And the VC must be
> reading from the 3B ECU temp sensor on the back of
> the head, right?
> Anyway, if a stuck open thermo, the warm up temp
> profile would be very slow
> and never reach anywhere near 185F unless you were
> really pushing on a 100+
> day.  So, I don't believe that is your problem.
>
> So, what's wrong with 185F op temp within a spec of
> 185/205F?  DFI if IAB!!
> And, unless you have previously calibrated the temp
> sensor and VC together,
> your readiings can be off by 10F.
>
> You are using the 7A thermo housing on your 3B, I
> assume?  You should be
> able to reach the housing hold down bolts thru the
> 7A's plastic side duct,
> where the housing's outlet pipe comes thru to
> connect to the lower rad hose.
> Once you get the thermo housing loose, I don't know
> where you go from there
> but, IMO, removing the IM won't help much.
>
> DFI if IAB!
>
> Bernie
>
> > From: Matt twentyV <matt_20v at yahoo.com>
> > Date: Tue, 22 Jul 2003 10:27:19 -0700 (PDT)
> > To: 200q20v at audifans.com
> > Subject: T-stat change advice
> >
> > Subject car is a '91 coupe quattro with a 3B
> engine.
> > I want to replace the T-stat as the engine temps
> > are a little low as read by VAG-COM block 000
> (hovers
> > in mid 180s vs. spec of 185-205) and radiator gets
> > warm immediately after starting.
> > Looking at the engine, I don't see how to get at
> > it without taking off the intake manifold.  Is
> there
> > a magic way to do this, or just bite the bullet
> and
> > pull the IM?  The coupe engine bay is a little
> more
> > cramped than the 200, the radiator is just a few
> > inches from the IM.  If pulling the IM is the
> > recommended course I can justify it better by also
> > replacing the MFTS and after-run sensor.  Any
> other
> > DFY-if-IAB-but-makes- sense-if- your-are-in-there
> > items?
> > TIA,
> > Matt Rooke
> > '91cq//20vt
> > '00S4//30vtt
> >
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