[s-cars] irregular temp guage readings

[Matthew Russell]

Folks- just wanted to give a BIG, public thank-you to all those (fast!) 
that replied.

will test MFTS, and proceed from there.  Nice to have a better 
understanding of all these sensors and what exactly they're doing.

Oh and BTW -  I think I still get heat when the gauge goes down, but 
maybe that's something I haven't been totally aware of...

-Matt

On Monday, January 30, 2006, at 07:43  PM, Tom Green wrote:

> Thats good, Matt.  The channel 51 readout is from the sensor feeding 
> your ECS,
> so it is getting the correct information.  The heat on your feet 
> doesn't plummet when
> the gage goes down does it ?   That sensor is the MFTS  and  is the 
> large brown sensor
> located under the intake manifold and below the coolant pipe.  You can 
> get to it.  It may
> have a large rubber boot protecting it.  Just don't break anything 
> else getting it out and
> have the new one ready so the coolant doesn't keep running out.   
> There has been discussion
> about what size wrench it takes.  It's big, maybe 32-36 mm, but I had 
> no problem getting an
> adjustable wrench on it.
>
> AutohausAZ.com had the best price I have seen recently.  YMMV
>
> The sensor for the CH 51 engine temp is on the back of the block.
>
> Tom
>
>> Date: Mon, 30 Jan 2006 16:29:02 -0700
>> From: Matthew Russell <skippertgore at msn.com>
>> Subject: [s-cars] irregular temp gauge readings
>> To: audi list <s-car-list at audifans.com>
>> Message-ID: <BAY101-DAV8F001BCF0D7DFBE7D5005C8090 at phx.gbl>
>> Content-Type: text/plain; charset=US-ASCII; format=flowed
>>
>> Have replaced thermostat twice now, boiled both thermostats and both
>> appear good. (opening around 87 C).
>>
>> HVAC channel 51 reads correctly (86-89 at operating temperature) -
>> meaning the MFTS is functioning, correct?
>>
>> Symptoms are that temp gauge will start to rise as car warms up from
>> cold, then will plummet down to almost nothing, then may come back up
>> in 5 minutes or so (time varies).
>>
>> Is the sending unit for the temp gauge located between the back of the
>> engine and the firewall, in a plastic fitting with coolant hoses on
>> either end of the fitting, held in by a clip?  Is this the likely
>> culprit? Can someone point me in the right direction?
>>
>> TIA,
>> -Matt, CO
>> 92 s4
>
>