Took my car into the dealership to replace breaks and update my inspection. After my car was serviced I have noticed that around 20 mph and 40mph the car makes a low vibrating noise. I called the dealership to ask them to take a look and see if they left something loose after the inspection. They told me I need new wheel bearings. My car wasn’t making this noise before having it serviced so I am a little confused.
So they diagnosed it over the phone? OK, no different than you getting a diagnosis from us over the internet.
Take it back, have it checked over. It might be the brakes, something they left un-done or it might actually be a rear wheel bearing. The car IS 10 years old with XXX,XXX miles on it (you don’t say), stuff does just wear out. It is very likely a coincidence. You may just not have noticed it before.