2013 TOUAREG Temp reading high

[Luksta]

New to me 2013 Touareg TDI Executive is in the Shop, had EGR & oil cooler replaced...now temp gauge reading high. As described by Tech at local VW dealership who replaced said components. He seems pretty competent but since he gave me details on the issue, my brain is troubleshooting.
Starts up and runs at 200 degrees steady, after about 30 minutes at idle, gauge quickly races to 280, but actual engine temp doesn’t rise. Troubleshooting advised to replace Temp sensor. When temp sensor, which was replaced by VW tech with VW OEM part, is disconnected, then gauge immediately reads 200 degrees again.
Any similar experiences, tips or insight greatly appreciated. Does anyone have access to full wiring diagram, what else is in that ground loop?

 

[TurboABA]

Umh.... what comes up on VCDS or VAS scans? Why is anyone just throwing parts at this system?

 

[Luksta]

Issues beyond explaining. Temp was a coolant bubble, as explained by tech...got it back and two days later, valve seat let loose and fragged bank 1. New engine on its way, ultimate reset. Guess the troubleshooting starts all over.

 

[TurboABA]

Sounds like troubleshooting never started.... at least you get a new powerplant.

 

[redbarron55]

New engine, not a bad solution.
Perhaps this is part of the cost of poor training.
I guess the cost is built into the cost of VWs in this country?
VW's biggest problem in selling cars in the US is the ratio of bad dealers/service to good.

 

[showdown 42]

Amen , redbarron