S3 Overheating HELP!

[mohammedzohaib]

Hi,

Be gentle as im a newbie

My audi s3 2012 has started to over heat but only on idle. The temp reaches 110 before the fans kick in. I have plugged it into vagcom and there are no errors i have also done a output test on HVAC and ran the fan control module and both fans kick in but if i run the cooling fan it doesnt work. Now obviously you would say the cooling fan not working right? I then turned the car off and let it cool down. The next day i fired her up and let her warm up to 90c plugged her back in vag and did a measuring block test on the ENGINE section of vag. I watched the coolant temp rise to 103c and the cooling fan kicked in and dropped the temp. This is really confusing are they working or are they not its driving me mad. What could the problem be.


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[Jnsio]

How long does it take for it to reach a 100 degrees?

 

[mohammedzohaib]

How long does it take for it to reach a 100 degrees?

If i start it up from cold start it take about 15mins to hit 100 but if i drive it about sometimes its already on high 100s like today i only went to town did a short trip and it was already on 107


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[leshkin]

Thermostat stuck closed maybe? Feel the comment pipes to check if they are all hot

 

[mohammedzohaib]

Thermostat stuck closed maybe? Feel the comment pipes to check if they are all hot

Ive checked the radiator pipes top and bottom and they are warm. Its driving me mad just constantly does it. Once it hits a certain temp the high speed fans kick in at 117c brings the car back to 90 but slowly rising in 10mins on idle. Will it be the thermostat?


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[leshkin]

Sounds to me like a thermostat or some sort of blockage is preventing coolant from circulating correctly. The fact the the pipes are warm does not mean that they are fine as it could just be ambient heat warming them up from outside rather than coolant inside. Worth a check.

 

[mohammedzohaib]

Sounds to me like a thermostat or some sort of blockage is preventing coolant from circulating correctly. The fact the the pipes are warm does not mean that they are fine as it could just be ambient heat warming them up from outside rather than coolant inside. Worth a check.

So does that mean my coolant fan is working because on initial start up if i leave it and let it warm up they kick in but after a drive they just dont work.

Cheers



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[leshkin]

The fan is just a way to get extra airflow over the radiator to help with heat exchange, but for that to work your coolant should also be circulating. It's hard to diagnose this without seeing it in person , so it might be worth taking the car to a proper mechanic.
Audi's have a very good coolant system generally, so should not overheat like that.
I assume that both fans are operating when the car is overheating?

 

[mohammedzohaib]

The fan is just a way to get extra airflow over the radiator to help with heat exchange, but for that to work your coolant should also be circulating. It's hard to diagnose this without seeing it in person , so it might be worth taking the car to a proper mechanic.
Audi's have a very good coolant system generally, so should not overheat like that.
I assume that both fans are operating when the car is overheating?

Yes both fans kick in when it overheats. Also if i put the AC on both fans work too.


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[leshkin]

Yes both fans kick in when it overheats. Also if i put the AC on both fans work too.


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It's got to be the thermostat stuck closed or a blockage in the coolant system that is preventing things from working properly.
It's not that hot for a S3 to be overheating like this at the moment. You should take it to a mechanic to do a proper diagnosis and fix it. Unfortunately, changing the thermostat on these engines is a a bit of a pain.

 

[mohammedzohaib]

It's got to be the thermostat stuck closed or a blockage in the coolant system that is preventing things from working properly.
It's not that hot for a S3 to be overheating like this at the moment. You should take it to a mechanic to do a proper diagnosis and fix it. Unfortunately, changing the thermostat on these engines is a a bit of a pain.

Well im getting the timing belt and water pump changed so i shall get them to change the thermostat n give coolant a full flush

Cheers buddy



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[smurfworth]

Well im getting the timing belt and water pump changed so i shall get them to change the thermostat n give coolant a full flush

Cheers buddy



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Could possibly be a damaged impeller on the water pump. Inspect the old one when removed and it might be a sign