My brakes squeak on my mkz the mechanic said it's because they heat up too fast

I JUST GOT BOTH OF THEM REPLACED AT THE DEALER PADS AND ROTORS

Bring back to dealer and demonstrate the noise/squeal, it may or may not be normal, DEPENDING on YOUR SPECIFIC driving conditions. If you do a lot of stop&go rush hour traffic , the heat may be a factor make sure they used the same 'grade' parts as the original.

Thank you