Ever since it got cold enough here (northern OK) to warrant using the heater in my 2013 MKZ Hybrid, I've noticed that the heater blower is really loud--loud enough to make me wonder if there are some "doors" or vents inside the heater system in the dash that are not opening properly. Once the car's interior warms up enough such that the heater needn't run on high, it quiets down quite a bit, but it really makes quite a racket when it first tries to heat the interior of my car. I expect some noise, of course, but this is loud enough that it makes me wonder if there's something amiss. Are others experiencing this? I'm hoping to hear from you, whether you are or are not experiencing the same thing. Thanks in advance.