Hope they used distilled water to make the right ratio.

 

There's only one thermostat on this car. But it is housed in a pipe that contains a bypass system. The bypass is used for fast heating of the engine and it can also direct the flow of coolant to the third radiator depending on demand. Like when you press the sport button.
So I suspect that the malfunctioning thermostat or temp sensor were not allowing the bypass system to operate as intended and stopping the flow to the 3rd radiator.

 

Interesting. Thanks for the info. I'll probably try to schedule a call with the mechanic who worked on the car to get the full run down.

 

Here read this and see after if the technician knows more than you :

 

And this :

 

This :

 

Finally :

 

wow