[s-cars] running cold after t-stat change

Wed Jul 1 12:12:08 PDT 2009

I had the exact same symptoms.  Highway driving dropped the temperatures.

First thing to try is to 'burp' the system.  If that doesn't work, drain the
system and refill.  Mine did the same thing and it required draining the
coolant system then refilling it.

To burp the system I put the front end up on jack stands and opened the
coolant reservoir.  Once the coolant started circulating I squeezed the
upper coolant hose repeatedly.  I saw bubbles enter the reservoir so I
lowered the car and added some distilled water up to the max line.  This
improved the situation but didn't completely cure it.

After several weeks of still having intermittent low temps, I pulled off the
coolant hose on the back of the head, and drained all of the coolant from
the lower radiator drain cock into a clean container.  Once it was all out I
closed everything up and refilled the reservoir with the drained coolant.
This is what ultimately worked.  I couldn't find the reference but I read
somewhere that it's good to 'prime' the system by prefilling some hoses but
I didn't need to do that.

Here are some tips:
http://forums.audiworld.com/showthread.php?p=18946259
http://forums.audiworld.com/showthread.php?p=18907526
http://forums.audiworld.com/showthread.php?p=18848059

Jim Gates

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Today's Topics:

   1.  running cold after t-stat change (Varon H. Fugman)
   2. Re:  running cold after t-stat change (djdawson2 at aol.com)
   3.   running cold after t-stat change (Bill Mahoney)
   4. Re:  running cold after t-stat change (Wylie Bean)
   5. Re:  running cold after t-stat change (David Kase)
   6. Re:  running cold after t-stat change (Andrew Beckert)

----------------------------------------------------------------------

Message: 1
Date: Tue, 30 Jun 2009 22:55:06 -0500
From: "Varon H. Fugman" <vfugman at globaldialog.com>
Subject: [s-cars] running cold after t-stat change
To: "'s-car-list'" <s-car-list at audifans.com>
Message-ID: <D0D3BE45AB564B28945DC617761D7DE2 at GT5228>
Content-Type: text/plain;	charset="us-ascii"

Patient: 1995 urS6, new 87C thermostat, new thermostat housing, new MFTS,
new blue coolant.  Car now does not warm up driving on highway.  Temp gauge
and climate control agree.  Today (with an chilly ambient temp of 56F) it
only warmed up to 59C (according to Area 51) after 10 miles of 65mph highway
driving.

1. New 87C thermostat was installed to replace the 80C thermostat that had
been installed at my last timing belt change.  I did test the new one in a
pan of water on the stove and it did open & close, although I did not check
the temperature at which it opened/closed.

2. MFTS replaced because I had never replaced it, so it seemed like a good
time while coolant was drained.

3. Thermostat housing was because of a leak. it appears to be made of the
same plastic as the heater-hose T fitting and after-run pump housing.  The
lip that seals against the t-stat o-ring was disintegrating and allowing
seepage.  The new housing has a difference from the original. it has a pair
of "fingers" inside which grab the thermostat.  They allow the housing to
hold the thermostat so both pieces can be installed on the engine together,
and they insure the thermostat is installed with the correct orientation.

I'm thinking either (a.) the new t-stat is defective and has stuck open or
(b.) the fingers on the new housing are somehow preventing the t-stat from
closing.

Any other theories?  Anyone else installed a new thermostat housing with
"fingers"?

Varon

'95 urS6 on the road again :-)

------------------------------

Message: 2
Date: Wed, 01 Jul 2009 00:49:25 -0400
From: djdawson2 at aol.com
Subject: Re: [s-cars] running cold after t-stat change
To: vfugman at globaldialog.com, s-car-list at audifans.com
Message-ID: <8CBC81E718E710A-F8C-22FF at FWM-D06.sysops.aol.com>
Content-Type: text/plain; charset="us-ascii"

 I'm betting it all on defective t-stat.

Dave

-----Original Message-----
From: Varon H. Fugman <vfugman at globaldialog.com>
To: 's-car-list' <s-car-list at audifans.com>
Sent: Tue, Jun 30, 2009 9:55 pm
Subject: [s-cars] running cold after t-stat change

Patient: 1995 urS6, new 87C thermostat, new thermostat housing, new MFTS,
new blue coolant.  Car now does not warm up driving on highway.  Temp gauge
and climate control agree.  Today (with an chilly ambient temp of 56F) it
only warmed up to 59C (according to Area 51) after 10 miles of 65mph highway
driving.

1. New 87C thermostat was installed to replace the 80C thermostat that had
been installed at my last timing belt change.  I did test the new one in a
pan of water on the stove and it did open & close, although I did not check
the temperature at which it opened/closed.

2. MFTS replaced because I had never replaced it, so it seemed like a good
time while coolant was drained.

3. Thermostat housing was because of a leak. it appears to be made of the
same plastic as the heater-hose T fitting and after-run pump housing.  The
lip that seals against the t-stat o-ring was disintegrating and allowing
seepage.  The new housing has a difference from the original. it has a pair
of "fingers" inside which grab the thermostat.  They allow the housing to
hold the thermostat so both pieces can be installed on the engine together,
and they insure the thermostat is installed with the correct orientation.

I'm thinking either (a.) the new t-stat is defective and has stuck open or
(b.) the fingers on the new housing are somehow preventing the t-stat from
closing.

Any other theories?  Anyone else installed a new thermostat housing with
"fingers"?

Varon

'95 urS6 on the road again :-)

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------------------------------

Message: 3
Date: Wed, 1 Jul 2009 08:52:12 -0500
From: "Bill Mahoney" <wmahoney at disk.com>
Subject: [s-cars]  running cold after t-stat change
To: <s-car-list at audifans.com>
Message-ID: <002b01c9fa53$22910a10$67b31e30$@com>
Content-Type: text/plain;	charset="us-ascii"

Second what Dave said:

"I'm betting it all on defective t-stat."

BTDT

Bill~alwaze doin'it 2x~M

------------------------------

Message: 4
Date: Wed, 1 Jul 2009 14:05:45 +0000
From: "Wylie Bean" <theringmeister at triad.rr.com>
Subject: Re: [s-cars] running cold after t-stat change
To: "Bill Mahoney" <wmahoney at disk.com>,
	s-car-list-bounces at audifans.com,	s-car-list at audifans.com
Message-ID:

<404596099-1246457144-cardhu_decombobulator_blackberry.rim.net-1166027572- at b
xe1106.bisx.prod.on.blackberry>

Content-Type: text/plain; charset="Windows-1252"

Exactly
Not sure but boiling water just to make sure it opened w/o checking @ what
temp it did so seems like a good way to make sure your stove works.  Not
much else.  
------Original Message------
From: Bill Mahoney
Sender: s-car-list-bounces at audifans.com
To: s-car-list at audifans.com
Subject: [s-cars]  running cold after t-stat change
Sent: Jul 1, 2009 9:52 AM

Second what Dave said:

"I'm betting it all on defective t-stat."

BTDT

Bill~alwaze doin'it 2x~M

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Wylie Bean
TheRingmeister at triad.rr.com
90 cq
91 90q20v
92 UrS4
08 Q7 3.6
Sent on the Sprint? Now Network from my BlackBerry?

------------------------------

Message: 5
Date: Wed, 1 Jul 2009 10:08:07 -0400
From: "David Kase" <dkase at dorma-usa.com>
Subject: Re: [s-cars] running cold after t-stat change
To: "Bill Mahoney" <wmahoney at disk.com>, <s-car-list at audifans.com>
Message-ID:
	<058B1C4576896745AB96826AB59CFC38096B31 at rmdc2.usa.dgna.net>
Content-Type: text/plain;	charset="us-ascii"

Shall we ask your wife of 50 years if this is true?

Kase

Bill Balonied:

Bill~alwaze doin'it 2x~M

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Message: 6
Date: Wed, 1 Jul 2009 11:23:11 -0400
From: Andrew Beckert <abeckert at gmail.com>
Subject: Re: [s-cars] running cold after t-stat change
To: "Varon H. Fugman" <vfugman at globaldialog.com>
Cc: s-car-list <s-car-list at audifans.com>
Message-ID:
	<3a0c724c0907010823l2577a12fyefca290e9fe9ff2f at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

Did channel 51 show proper readings before replacing these parts?  I have to
ask, as channel 51 reads the sensor in the coolant-T behind the block (not
the mfts) and I've had this sensor go bad before and only read up to the
50's.  If you aren't sure if it was working before, I would replace it.  If
you need part numbers, shoot me an email.

Andrew

------------------------------

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