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  #21  
Old 22nd February 2018, 01:42 PM
carl81 carl81 is offline
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Was my best guess at the overheating issue as looking around the internet it seemed quite a common problem. Only the thermostat was replaced.

One gem I think I’ve missed is that when it was idling in the garage the heater was all set to HI. Obviously once I started driving I turned it down. Was the aux pump just enough to keep it cool?

Last edited by carl81; 22nd February 2018 at 06:11 PM.
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  #22  
Old 22nd February 2018, 09:22 PM
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Goran Goran is offline
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I have watched my Aux fan go into 'oh ****' mode, I am pretty sure it kicks in around 110C
I cant think of any other good explanation why the temp quickly goes back down after hitting 110C
Also I am confident I confirmed my viscous clutch is not engaging, I suspect this is the combination which sends the car on a overheat cycle in warm traffic, when outside temps are around 27C and above.
My thermostat is fairly new Audi original. Belt changed by pros
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  #23  
Old 22nd February 2018, 09:26 PM
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Goran Goran is offline
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Quote:
Originally Posted by carl81 View Post
Thanks for all your replies. I will check the viscous fan. However wouldn’t it overheat at idle even more than when in motion if a fan had failed? My mechanic that did the thermostat left the car running for 15 minutes and it was running when I arrived. We had a chat, I paid up, got in the car and still at 90. Only once driving on a bypass (so not in traffic) did it begin the creep up. That’s the opposite to what my brain tells me when I think of how engine cooling works.
Yes your problem sounds different to mine. Mine cools back to 90C within minutes when it starts moving
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  #24  
Old 22nd February 2018, 10:54 PM
HPsauce HPsauce is offline
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Quote:
Originally Posted by carl81 View Post
Only once driving on a bypass (so not in traffic) did it begin the creep up. That’s the opposite to what my brain tells me when I think of how engine cooling works.
Maybe with an old-school engine that gets cooled by passing airflow, but a big V8 is tightly packed in and needs help!
On the bypass it's generating a hell of a lot more heat internally than just ticking over idling, that has to be taken away somehow.
I recall when I first got an S8 and opened the bonnet after my first drive round how unbelievably hot it was under there and for how long, but that's normal.

It sounds like something may not be 100% but nothing like as bad as you seem to suspect.

At the end of the day if it all works as expected is there anything to worry about. e.g. Does coolant boil out of the expansion tank, does the engine run rough when cold or hot?
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2003 D2 FL S8. Irish Green Pearl/Beige. Solar sunroof, auto-dim mirrors, electric rear seat functions, ski hatch retrofit; extended leather. Aftermarket DVB-T, reversing camera and full XCarlink (Bluetooth etc.).
2016 Volvo V40 T5 Cross Country (4WD) with ALL the toys including adaptive cruise etc. etc. Osmium Grey with Blonde/Charcoal leather interior. Polestar performance "optimisation". (A much rarer model than a D2 S8 by the way!) Oh, and a brand new engine at just under 30,000 miles on the factory one!
Finally: gone, but not forgotten.....
1998 D2 PF S8. AgateGrey/Platinum. Every option (I think) except electric rear seats, tiptronic steering wheel, ski hatch, towbar & dimming door mirrors.
e.g. Cruise control, NavPlus/TV, Bose, GSM, Xenons, Solar roof, Parking sensors, Alcantara/leather everywhere of course. (internal dimming mirror added later)
1998 (very early) Ford Focus 1.8 Zetec; ABS/TCS, Heated screen/mirrors, Aircon, Auto-dim mirror, Leather, Trip computer, Cruise control, OEM Ford SatNav with CD changer.
And before that a lot of Rover 800s, a few oddities, a lovely Triumph Dolomite 1850HL with Overdrive and way back in my schooldays an Austin Seven aka Mini 850!
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  #25  
Old 23rd February 2018, 07:47 PM
carl81 carl81 is offline
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Damn vcds couldn't get it to work. I think my cable is broken. Anyway see attached I didn't dare go any higher than that. It was running absolutely fine. I guess there is a simple test to see if the water pump has gone?
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  #26  
Old 23rd February 2018, 09:15 PM
Davey Blueeyes Davey Blueeyes is offline
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Quote:
Originally Posted by carl81 View Post
Damn vcds couldn't get it to work. I think my cable is broken. Anyway see attached I didn't dare go any higher than that. It was running absolutely fine. I guess there is a simple test to see if the water pump has gone?
Do you have a flux capacitor in your car? The date on it is showing 5th March 1999!!

Does the overheating kick in around 88mph?!
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  #27  
Old 27th February 2018, 10:25 AM
carl81 carl81 is offline
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Assuming its the water pump does anyone know which cam belt kit I need? Any recommendations or links?
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  #28  
Old 27th February 2018, 10:34 AM
HPsauce HPsauce is offline
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It think that would be a big (potentially expensive) assumption. Does the radiator warm up?
__________________
2003 D2 FL S8. Irish Green Pearl/Beige. Solar sunroof, auto-dim mirrors, electric rear seat functions, ski hatch retrofit; extended leather. Aftermarket DVB-T, reversing camera and full XCarlink (Bluetooth etc.).
2016 Volvo V40 T5 Cross Country (4WD) with ALL the toys including adaptive cruise etc. etc. Osmium Grey with Blonde/Charcoal leather interior. Polestar performance "optimisation". (A much rarer model than a D2 S8 by the way!) Oh, and a brand new engine at just under 30,000 miles on the factory one!
Finally: gone, but not forgotten.....
1998 D2 PF S8. AgateGrey/Platinum. Every option (I think) except electric rear seats, tiptronic steering wheel, ski hatch, towbar & dimming door mirrors.
e.g. Cruise control, NavPlus/TV, Bose, GSM, Xenons, Solar roof, Parking sensors, Alcantara/leather everywhere of course. (internal dimming mirror added later)
1998 (very early) Ford Focus 1.8 Zetec; ABS/TCS, Heated screen/mirrors, Aircon, Auto-dim mirror, Leather, Trip computer, Cruise control, OEM Ford SatNav with CD changer.
And before that a lot of Rover 800s, a few oddities, a lovely Triumph Dolomite 1850HL with Overdrive and way back in my schooldays an Austin Seven aka Mini 850!
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  #29  
Old 27th February 2018, 02:14 PM
MikkiJayne MikkiJayne is offline
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Take the belt covers off and see if the belt is tight on the pump pulley. Sometimes the crank can kick back under compression when the engine stops which can loosen the belt a little but it shouldn't be slack.

If there is any slip on the pulley, see if you can spin it by hand and see what it feels like - looking for clunks or odd noises, or a grumbly bearing.
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  #30  
Old 27th February 2018, 05:43 PM
carl81 carl81 is offline
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So I’m not convinced all of the radiator is warming up:

https://youtu.be/GIg8nAgkv7o

And and that temp would have expected the fan to kick in which it did not. However think that is a red herring as it doesn’t cool down once in motion.

Re the pulleys may need my mechanic to look at that might be getting too much for me!
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