Tiguan 2.0 tdi overheating at high speed

Hi
I recently got me a Tiguan 2.0tdi and it overheats only at high speed. If I slow down the temp needle comes back to normal. Also it does not always do it. I have replaced the cap on the water tank and the bottle itself, the thermostat, the waterpump, the radiator even bridged out the pipe that goes to the heatercore so that water flow does not go through it, thinking it might be clogged. No luck problem still occur. Even had a pressure test done and sniffer test done to check for CO2 in the water system. Any other Ideas?

Is it DSG transmission? Any chance the DSG thermostat got stuck closed?
Also, are both radiator fans working fine? You can easily check that at idle. You need to turn on the A/C and after a few moments they should spin up, both of them.

Henrick, thanks for replying. I dont know will have to check. Also yesterday I could drive at speeds of 130km/hr on cruise control for about 25km with the temp needle on its happy place. Then out of the blue it started creeping up slowly, then i dropped speed to 90km/hr and the needle came back again. This is the problem it does not have a pattern, how is it possible that the one day I cant try to go higher than 100km/hr and the next day I can go 120 or 130 for 20 to 30km with the temp needle remaining in the middle on its normal place.

If the temperature needle goes over the center position you must have some serious overheating (unless the cluster behaviour is modified, like mine is). Overheating will result in warped cylinder head as the needle starts to move past 90 *C mark only at coolant temperatures of 115 *C or above.

What are ambient temps in your region? Maybe the car is having a regen?

Any chance you could do G62 sensor logging using VCDS and share the log?

Henrick said:

If the temperature needle goes over the center position you must have some serious overheating (unless the cluster behaviour is modified, like mine is). Overheating will result in warped cylinder head as the needle starts to move past 90 *C mark only at coolant temperatures of 115 *C or above.

What are ambient temps in your region? Maybe the car is having a regen?

Any chance you could do G62 sensor logging using VCDS and share the log?

Click to expand...

Hello i have a question regarding the temprature gauge you say that you have a modified cluster behaviour what does that mean. does it mean that cluster shows the right temperature and is not always on the center like on newer VW"s.

Yes, that's absolutely correct. It shows temperature exactly the same as G62 sensor reports.

Henrick said:

Yes, that's absolutely correct. It shows temperature exactly the same as G62 sensor reports.

Click to expand...

Is it possible to modify it with Vag- com or do you have to modify the cluster. I ask this because my dad has a 2005 VW multivan 2.5TDI and the gauge always goes on 90°C and i have read that it only moves if the temperature goes over 115°C

No, not possible. You need more professional/expensive equipment for that, like Carprog.

Henrick said:

No, not possible. You need more professional/expensive equipment for that, like Carprog.

Click to expand...

It's nice to know that it's possible because what's the point of gauges if they dont show the right temperature.

No. As far as I can tell, it was not modified. We are going to change the radiator hose as it might be collapsing at speeds over 120Km/hr. Only problem is I have to get it from VW as I can't get it anywhere else and it is not cheap. To make it worse, I have to order it fron VW as they apparently don't keep stock of it at the service centre's here in SA.