Hello dear friends!

 

I own a Superb 2.0 TDI with DSG transmission.

 

I own the car for 5 years and when the car got to the operating temperature (90 degrees) it stayed there during the whole trip. 

A few days ago I started having some strange issues with coolant temperatures. I was driving down the highway and after some 400 kilometers I made a break for about 45 minutes. After that I continued and after about 100 kilometers I noticed it was a bit colder in the cabin. I looked at the temperature gauge and it was showing around 70 degrees. It stayed like that for the next 100 kms untill i got to the city. Then I left the car for 2 hours and continued driving for the next few days and the coolant temp would always get to 90 degrees as usual. I then went on to the highway and drove for 350 kilometers and the temperature was 90 degrees during the whole trip and just at the end I was going downhill for around 10 kilometers. I was watching the temp gauge closely and it was showing 90 all the way to the end and only at the last kilometer iz dropped to 70 degrees. As I entered the city it slowly got back to 90.

yesterday I was going down the motorway and everything was fine. 
 

Is it possible that one of the thermostats is getting blocked somehow or there might be some other problem?!

 

I changed the DSG thermostat 4 years ago but then it was simple. It would only get to 90 degrees going uphill and all the rest of the time it was around 70 so it was straightforward what to do...

I would have said DSG stat again. But like you only changed mine once when the temperature needle went to 90 and back down again or indeed never reached 90 

Just had both my thermostats changed. Now I have heat again ! The garage said the main ones rarely fail and it’s usually the DSG one that goes. 

I will try wit the DSG thermostat again. But I find it strange that sometimes everything is ok, I can drive for 300 kilometers and the temp is rock solid 90 degrees no matter if I go uphill or downhill and then at some point (usually while going downhill) it goes down to 70 and it is difficult to bring it back to 90...