I drive an Innova, it do have a turbo but no intercooler.

The SA said to cool down the engine between 2 to 5 mins.

The reason behind this is to release the build up pressure in the turbo itself after driving the car above 80 KPH... and during LONG drives.

And if you're city driving and haven't reach the speed 80 KPH and above, I guess it's safe to not cool down the engine.

BUT for me, city driving or long drive... I still follow what the SA advised.

HTH