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How hot does your S8 run?
Posted: Mon Aug 17, 2026 8:11 am
by SharkGill
Been meaning to ask for a few weeks. With recent temperatures regularly in the 30s I’ve noticed my coolant temperature hitting upto around 110 during ‘spirited’ drives. Poodling around in traffic the temps go back down to the normal 90 ish so I think water pump is functioning correctly. I did try testing the viscous fan clutch with the old newspaper method and I was able to stop it. Also haven’t heard the normal loud woosh from the fan at any point when they usually are engaged. Thoughts anyone?
Re: How hot does your S8 run?
Posted: Tue Aug 18, 2026 6:58 am
by The_Laird
I’ve had similar problems a couple of times in my ownership and it’s been either thermostat/pump (when a garage fitted non-Audi parts) or the fan. Apart from that, My S8 sits at 90 even in the recent heatwaves.
Re: How hot does your S8 run?
Posted: Tue Aug 18, 2026 11:08 am
by MikkiJayne
Mine runs at 90, always. Even 30 degrees ambient in attack mode round the Nurburgring
If its at 110 both fans should be on max speed and sounding like jet engines. Sounds like the viscous clutch is not clutching, and possibly the electric fan is also having issues. The electric fan should come on at speed 1 with the AC. It then uses the thermoswitch in the rad for speed 2, and the cluster has an 'oh shit' trigger for speed 3 which should definitely be on at 110 - pretty sure the set point for that is 105.
I have an electric fan conversion instead of the visco and mine will sit there with both fans on #1, even in this weather.
Re: How hot does your S8 run?
Posted: Tue Aug 18, 2026 7:57 pm
by SharkGill
Thanks for the input reveryone. I’ll be changing viscous clutch, waterpump and thermostat soon. Second pic is a short drive through town traffic, first pic is after a spirited drive for 10 miles on the M4 (15mins apart) Temps are definitely not as they should be
Re: How hot does your S8 run?
Posted: Tue Aug 18, 2026 8:03 pm
by SharkGill
MikkiJayne wrote: Tue Aug 18, 2026 11:08 am
Mine runs at 90, always. Even 30 degrees ambient in attack mode round the Nurburgring
If its at 110 both fans should be on max speed and sounding like jet engines. Sounds like the viscous clutch is not clutching, and possibly the electric fan is also having issues. The electric fan should come on at speed 1 with the AC. It then uses the thermoswitch in the rad for speed 2, and the cluster has an 'oh shit' trigger for speed 3 which should definitely be on at 110 - pretty sure the set point for that is 105.
I have an electric fan conversion instead of the visco and mine will sit there with both fans on #1, even in this weather.
Funny coincidence, I just came back from the Nurburgring this weekend. My first time on track so I took the V5 Golf, had a blast. The plan was to take the S8 but I still need to do front suspension arms and I have the temperature issue. I was also considering an electric fan conversion but I guess it’s not really needed for a daily driver.
racetracker_51735552_736853.jpeg
Re: How hot does your S8 run?
Posted: Wed Aug 19, 2026 3:48 pm
by MikkiJayne
Awesome
How busy was it? We stopped going because TF just got too busy at the times we could go and was getting unacceptably dangerous. You don't have an angry BMW nibbling the paint off your back bumper so maybe it wasn't too bad?
This is my most favourite pic of my car
racetracker_32053871_509936.jpg
Re: How hot does your S8 run?
Posted: Thu Aug 20, 2026 6:43 pm
by SharkGill
That looks Epic! waterpump and thermostat arrived from TPS this morning £187 all in. What I failed to realise is that the pump is timing belt driven so relevant tools are also on order. I really wanted to take the S8 to the Ring next week but I don't think I'll have the time to get it ready so will likely go in the V5 again.