[s-cars] Local, intermittent overheating !???!?!

[Tom Green]

I agree, Mark.
Plus, the Canuk head already shows some problems with
the logic circuits, probably from overheating.  ;-)  I suspect
not much to salvage there.  ;-)

Tom  '95 S6


> Earlier, much was written about this saga:

> Date: Wed, 15 Dec 2004 20:45:31 -0500
> From: "Mark Strangways" <Strangconst at rogers.com>
> Subject: Re: [s-cars] Local, intermittent overheating !???!?!
> To: Vincent Fr?geac <vfregeac at sympatico.ca>,	"'audi s-cars list'"
> 	<s-car-list at audifans.com>
> Message-ID: <00bf01c4e310$ee38d3a0$6400000a at Dell9100>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> 	reply-type=original
>
> There just might be some air in the head, not likely though.
> With a thermostatically controlled oil cooler it will get to 100 C or 
> so and
> hold there if it can.
>
> My best guess would be to get that thermostat out ASAP. Don't wait as 
> you
> risk trashing your head, the aluminum one, not the French Canadian one.
>
> Mark
> ----- Original Message -----
> From: "Vincent Frégeac" <vfregeac at sympatico.ca>
> To: "'audi s-cars list'" <s-car-list at audifans.com>
> Sent: Wednesday, December 15, 2004 7:57 PM
> Subject: [s-cars] Local, intermittent overheating !???!?!
>
>
> Hi all,
>
> Once again, my S6 is puzzling me. On my way to work, this morning, I 
> noticed
> the check light was on. I started to look at gauges to see if 
> something was
> really going wrong and, no, every needles are right where they should 
> be.
> Huh? Every needles? My car is one of those who shows 70 something as 
> coolant
> temp on the highway when the channel 51 displays a very stable 89-90C. 
> This
> time, the coolant temp on the dash is right on 90C. So I started to 
> play
> with the HVAC controller and channel 51 shows 112C! How! The next exit 
> is
> within reach. In less than 500m, the channel 51 reach 118C. Something 
> really
> goes wrong. So I took the first exit - to notice that channel 51 
> dropped to
> 111C during the exit ramp, probably because I'm coasting - park the 
> car in
> the gaz station parking lot and pop up the hood. Coolant everywhere, 
> one
> boiling inch remaining in the bottom of the coolant tank and electric 
> fan
> working. That's the first time I see it working and I notice it's out 
> of
> balance or rubbing somewhere as it's massively vibrating.
>
> So, first step, let everything cool down, the engine and my head. 
> Towing my
> car is the last solution I want to think of as I'm in the middle of 
> nowhere
> and it will probably take two hours before I can have the required 
> flat bed.
> I'm 30 min. from home. If I drive 10 min, stop 10 min, I can probably 
> reach
> my trusty 90Q20V and be at work before the second meeting. So, I look 
> for
> water - no way to find the pink stuff in the middle of nowhere - feel 
> the
> coolant tank, wait until the channel 51 display a confortable 92 and 
> start
> the trip back to home to see how long it will take before I reach 
> 105C, the
> point where I've decided to stop and let the car cool down again. 
> After 1min
> of driving, the car have cooled down to 89C and stay there. 5km later, 
> it's
> still at 89C. So, as I'm not so far from work, I decided to take a 
> chance.
> And the channel 51 temp stayed at 89C, perfectly stable, when the dash
> displayed the usual 70C. Some shit happened, I don't know what, buit 
> now
> it's gone. Good news.
>
> So this evening, back to home. I took no chance and tuned the HVAC on
> channel 51 from the beginning. Temp is climbing at it's usual pace,
> everything seems OK and when I reach the highway, 5min later, the 
> channel 51
> just reached 87C. 10 seconds later, it reach the usual 89C while the 
> dash is
> still at 70C, everything is as usual. But it doesn't stop there, 90, 
> 91,
> 92... Up to 99C where it seems to stabilize, probably because I'm 
> going at a
> slow 55mph to try to slow down the temperature raise. Looking at the 
> dash,
> the water temp is right in 90C, oil temp is just below the first thin 
> mark
> as usual. And I start the drive-cool down cycles until I arrive home. 
> At one
> point, while driving on the highway, the channel 51 suddenly fall from 
> 104C
> to 92C while the dash temp was falling from 90C to the usual 70C. 
> Then, it
> started to climb back to the 105-110C which was the maximum I allowed 
> before
> I stop the engine for cool down.
>
> Now, in my mind, all that point to an intermitently stuck close Tstat,
> especially the temp falling down from 104 to 92 while cruising on the
> highway, but I've still some points I would need your usual wisdom:
> - Why the dash temp is right on 90C and very stable when the channel 
> 51 says
> it's overheating and displays temperature from 92C to 118C.
> - Why the oil temp stays perfectly stable, just below the first thin 
> mark,
> where it has always been - except during very spirited driving - when 
> the
> water temperature is everywhere between 89 and 118C.
> - Why the dash temperature is stable (independant of speed) when the 
> channel
> 51 fluctuate (overheating) and why the dash temperature fluctuate 
> (depending
> on speed) when the channel 51 is stable at 89C.
>
> Besides, I've never heard of a Tstat stuck close, intermitently or 
> not. Any
> BTDT?
>
>
>
>
> Vincent.