I am used hearing the turbo when driving on other cars I had.

On my XC60 2018 T5 I don't hear the turbo at all.
Is this normal or does it mean that the turbo is not working properly?

 

If you hear a whine from a turbo the clearances are not perfect. Really noisy is the sound of the turbine wheels touching a housing. If you hear air sucking when accelerating or blowing off when decelerating - that has has to do with noise insulation. - What sound are you missing?

 

I am used to hear whistling sounds from the turbo looking at other cars I know and drove...

So you are saying that a turbo on the T5 should not make a sound at all?

Some people also say that if you don't hear anything the turbo does not work properly or is broken.

 

My 2001xc70, 2001v70t5, 2002xc70, 2004 xc90t6 (twin turbo), 2015xc70 t6, 1981 240t, 1986 Maserati Buturbo, 1986 Porshe 944t - all had almost silent turbos. Well the Maserati turbos had to be rebuilt twice - that car was a mistake>

If the turbo is "broken" as in seized or shaft snapped (saw a A4s audi like that once) - the car will be VERY sluggish - like having a blockage in the exhaust system. At that point they usually dump oil into the exhaust also. And if bushings are worn the fan can eventually touch the housing - and be very noisy.

Quiet is good - means the clearances are perfect and the bushings are not worn. A turbo is simply 2 fan blades connected together with very little clearance between the housings and the blades to compress the air.. Try to time 0-60 if you think your car is sluggish.