wind noise from the floor of my M5

Dear guys,

I am new at this forum. Currently, I am living in Rotterdam, Netherlands and we just bought our mazda 5 last week. It's a 7-seat verstion which is a little bit different from the us version. Besides that everything is the same as the US version.
My question is that we can hear strong wind noise when driving on the highway at the speed over 100km. It sounds like coming from underneath the third row of the back seat but we don't know where it is exactly. Does anyone of you similar experice and could you recommend some solution for this ? Thanks and best regards from Netherlands.

Hello and welcome to the forum!

Are you sure it is wind noise? I had what I thought was wind (or tire) noise coming from the same area at high speed (2009 Mazda 5) that turned out to be coming from a defective wheel bearing.

Having said that, Mazda 5 is a great car but (in my opinion) it is not a great highway cruiser. While it is a pleasure to drive and (again, in my opinion) is an ultimate vehicle for a city family, it can be quite noisy on the long highway drives...

There is no sound insulation there. even carpet has no sound insulation in it.
Add some and will be better.

First thing I would check, is remove the spare tire and make sure that all the rubber plugs are in place at the bottom of the spare tire well. There may only be one, but if it is missing, or loose, that would allow a large amount of additional noise into the cabin. Also check the condition of the rubber seal around the hatch, if it is torn or missing that could also be your culprit. What other have said is also true, the 5 is mighty thin on sound insulation under the rear cargo floor adding some cannot hurt.

Also, the underside between the wheels has plastic skirts where the front and center seating are up above. The plastic fasteners can break and these skirts then can move with the air currents under the car. That can generate some wind noise as well, especially with all the poor insulation.

thanks for all your advice. Today i went to one of our local Mazda dealer in Rotterdam. They did an overall check of the car. Unfortunately, they found lots of problem. Three major things are: airco compressor is dead, rear suspension absorbent is leaking and breaking disk need to be changed. They asked me a rediculous price for changing those things. Guess what they ask for 2500 euro for those three things. I know most of the dealers are greedy, but this one is an outstanding. Luckly, i escaped in the end. Since you guys are more experienced with Mazda 5, i wonder what is the reasonable price for changing the compressor , all 4 discs, and the rear absorbent? Since i am in Europe and there is no Mazda factory in EU. Could you recommend some US based reliable seller for the components and the one who can also do the international delivery to Netherlands. Thanks in advance.