New Thermostat?

[purdy1984]

Been having issues with temp for last few months so been working my way through possible causes and thinking now it might be thermostat. When sat in traffic and not moving the temp goes above 90 and on a few occasions has maxed out at 130 on temp gauge. Previous had OBD readings which also confirms its getting at high at 125 at times. I've replaced coolant temp sensor, have new cambelt and water pump and confirmed both fans work while car is running - they also spin for quite a few minutes after the car is turned off after a decent journey and or hot day. I have no leaks and all is otherwise ok so could it be the thermostat is stuck closed so coolant is not actually circulating through the car? Could it be checked anyway (VAGCOM?).

Thanks

 

[NHN]

Check all coolant pipes on a hot engine, if some are not boiling hot, then its not circulating imho.

 

[Troubs12]

Check all coolant pipes on a hot engine, if some are not boiling hot, then its not circulating imho.

Also have the cap off slowly push the throttle pedal down you should see the coolant returning to the bottle either a stream or a swirl in there. But it sounds like the thermostat is stuck shut of the water pumps failed


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[Alex.S3]

I’ve replaced the thermostat on my TT and S3, the Tt failed open fully so only got up to temperature in traffic but would drop again at speed.

The S3 was a bit more subtle and would only drop a small amount at speed, after a new thermostat it was solid.

I guess what I’m getting at is they both failed open rather than sometimes closed.

not sure how helpful that is.

 

[purdy1984]

thanks all - will try and get under car at weekend to check all pipes hot top and bottom and not just from engine heat. Thought it was more common to be stuck open but not sure what else it could be if not that TBH

 

[Audi A3 S-Line 8p tdi]

Been having issues with temp for last few months so been working my way through possible causes and thinking now it might be thermostat. When sat in traffic and not moving the temp goes above 90 and on a few occasions has maxed out at 130 on temp gauge. Previous had OBD readings which also confirms its getting at high at 125 at times. I've replaced coolant temp sensor, have new cambelt and water pump and confirmed both fans work while car is running - they also spin for quite a few minutes after the car is turned off after a decent journey and or hot day. I have no leaks and all is otherwise ok so could it be the thermostat is stuck closed so coolant is not actually circulating through the car? Could it be checked anyway (VAGCOM?).

Thanks

I would bet on the thermostat, not a hard job like everybody says. Remove the alternator which is simple then two 10mm bolts on the housing, I've had issues with mine recently so changed both temp sensors, if you wasn't aware there was two then maybe check the one in the thermostat housing first if that's not the one you replaced. Hope this helps. I've done all coolant related issues with this car so I will help in any way I can, just drop me a reply.