Engine Coolant Temperature Gauge question

[Dave Eaton]

the later audi's have 2 separate (but combined) temperature senders.  g2 and
g62.  g2 feeds the ecu while g62 is for the instrument cluster.  the
instrument cluster display fibs.  deliberately.  it will not show any
variance from 90c until temps are at least 10c above that.  and it will show
90c well before that temp is actually reached.  this is to stop the punters
complaining about variable temps. the instrument gauge will eventually
signal variance when provoked by high temps, just don't expect it to reflect
actual temps most of the time. 

the only way to really tell your temp is to log the values of g2.  

you can do this through using the hvac cheat codes.  on the c5, location 34
is the g2 and 35 is the instrument cluster readout.

hth
dave
'03 rs6
'04 allroad tdi

-----Original Message-----

Message: 3
Date: Tue, 22 Jan 2008 13:00:38 -0800
From: thejimrose <thejimrose at gmail.com>
Subject: RE: Engine Coolant Temperature Gauge question
To: quattro at audifans.com, david.giannandrea at sbcglobal.net
Message-ID:
	<298352bd0801221300k34884589x368a409bc91c5e3f at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

>
> Question 1:
> Should the thermostat keep the coolant temperature relatively constant?
> Even
> at low temps and highway driving?
>

yup. mine  is always  rock steady  on the 1/2way mark on the gauge. from 110
in sonoma to 15 in tahoe.

Question 2:
> What is the usual position of the needle when driving?


1/2 way on the gauge.

And what is the
> position of the gauge when the radiator fan kicks in?


no change on mine.

Question 3:
> I think the dots for positions 1 and 7 are calibration test marks. If 
> I remember correctly, the Bentley shows usage of a "Special Tool" to 
> test the gauge. More than likely the tool is just a rheostat. Does 
> anyone know the resistance values at the two test positions?
> Answer: not me.


me neither.

Question 4:
> Does anyone have a simple method of measuring the coolant temperature 
> with an external thermometer?


laser thermometer  hitting the engine /  radiator at various points? but
agreed, the temp sensor is the right place, coming out of the block.

>
> Answer: You need to read temp of coolant inside the engine or 'read'  
> the temp sender.
>
> Conclusion: Get a new thermostat. Didn't we just do this one?


+1. might wanna flush the coolant, change the temp sender too while 
+you're
in there.


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