Coolant temperature: Too high warning

[Cruz653]

Got this message yesterday while driving. Loud Fan comes on as soon as it appears. When at a stop light and car is idling, fan will turn off and no more warning light; then I start driving and warning will eventually appear again after a few minutes. I checked for codes and have none. Taking the car to the dealership this weekend but wanted to know if anyone has experienced this? I’ve searched through the forums but it’s mostly people that have the fan stay on even after ignition is turned off, which for me it has not done that so not sure if it may still be the thermostat or water pump. Also the engine temp seems to be working as normal.

[Cruz653]

Forgot to mention 2018 Audi S5 with nearly 38K miles. I am on APR stage 1 with CTS intake and Intercooler

[RUNSGR8]

When I had this on my 2018 RS5, it was because there was a coolant leak. Coolant is highly pressurized and any air that gets into the system will cause the coolant to dramatically increase in temperature. Do you see any clear fumes coming from under the hood when you pop it open after driving? You can also smell coolant if it's actually leaking.

[Cruz653]

No coolant leak, it’s actually been at the dealership since Saturday. They can’t find anything wrong or any leaks so they’re going to just replace the entire cooling system.

[Alexfica04]

Same problem with my s5 . I changed the thermostat and one day the coolant temperature is high and next day all is fine . I don’t know what is the problem

[c99]

Same problem with my s5 . I changed the thermostat and one day the coolant temperature is high and next day all is fine . I don’t know what is the problem

So it is water pump.

[Alexfica04]

I don’t have any leak on water pump so why sometimes is working and sometimes not , I saw another thread and they speak about coolant valve solenoid .

[Alexfica04]

I solved the problem after i changed switching valve (solenoid valve coolant )

[Cuongcm411]

I solved the problem after i changed switching valve (solenoid valve coolant )

Hi Alex,
By any chance if you can post the link to get coolant solenoid valve here? I can't seem to locate it on the internet, thank you.

[V6Quatt]

I have heard the housing can leak too was there any pink residue when opening the bonnet