AudenHoggart Posted March 15, 2013 Report Share Posted March 15, 2013 We've had our C Max about 3 weeks and are on our first extended road trip. So I really like the way it drives. I'm getting about 37 mpg which I regard as OK for the initial period. Today, however, we had a very unsettling experience. We were driving down the Natchez Trace, about ten miles from the end in Natchez, when we pulled onto a side road to see a large Indian mound. My wife took some pictures from the car and then we headed on to Natchez. Once we got back on the main road and accelerate,probably only to about 50 mph, the car started making a thumping noise that seemed to be coming from the rear.. It's the type of noise I'd associate with a flat tire but it didn't feel like a flat tire. I thought maybe a branch was caught under the car, pulled over to the side and found nothing. I immediately thought something was wrong with the battery, but all the gauges were normal and I was getting no warnings. Luckily, it was still afternoon on a weekday, so I drove straight to the Ford dealer in Natchez. Along the way I realized the rear left window was open (and I'd probably opened it inadvertently when I opened the window for my wife to take pictures.) When I closed the window the thumping went away, but it returned when I reopened it. When I got to the Ford dealer, the salesperson laughed and said he's had the same thing on a number of Ford models. With the window open and the air circulation system operating it sets up something in the air circulation flow in the car and makes that noise. He also said it makes his wife light-headed and my wife said the same thing! So, at least for now, everything is cured and car seems to be running fine. This is the first I've heard of anything like this. Does anyone have any comparable experiences? Does it sound like something else that needs attention? Quote Link to comment Share on other sites More sharing options...
valkraider Posted March 15, 2013 Report Share Posted March 15, 2013 We have a rule, there can never be only one window open. The air pressure fluctuation hurts my head.... :) Always have to at least crack a second window. Quote Link to comment Share on other sites More sharing options...
Max Power Posted March 15, 2013 Report Share Posted March 15, 2013 I've noticed it too. The car is un-drivable with just one of the rear passenger windows open. I've made my peace with it. Quote Link to comment Share on other sites More sharing options...
valkraider Posted March 15, 2013 Report Share Posted March 15, 2013 It's been that way for us in every car we have owned since they started making them seal up tight. It's also noticeable with sunroofs that open. Certain positions cause cavitation in the cabin air that hurts. Cracking another window helps immensely... It gets rid of the pressure. JAZ 1 Quote Link to comment Share on other sites More sharing options...
Maximus Posted March 15, 2013 Report Share Posted March 15, 2013 The phenomenon is called "packing" and is present in newer cars that are well-sealed. Incoming air "packs" into the car and has no way out, unless you open a second window. The owners manual mentions this, and suggests opening a second window. JAZ 1 Quote Link to comment Share on other sites More sharing options...
RachelnLa Posted March 15, 2013 Report Share Posted March 15, 2013 I noticed this in my suburban yrs ago. I HATE to ride with windows down. What girl wants her hair stuck to her lip gloss or beating her about the face like tiny whips! Lol My husband has quickly learned. Windows go UP. Quote Link to comment Share on other sites More sharing options...
C-MaxJaxon Posted March 15, 2013 Report Share Posted March 15, 2013 The comment in the manual is on page 96. "Note: You may hear a rumbling noise when one or both of the rear windows are open. Lower a front window slightly to reduce this noise. Press the switch to open the window. Lift the switch to close the window." Quote Link to comment Share on other sites More sharing options...
GS Dave Posted February 17, 2014 Report Share Posted February 17, 2014 I was wondering about this. Of all the cars I have owned, this one is the worst for it. If it is a sign that it is well sealed, I guess that is a good problem to have? I can't stand it though. It really can hurt the ears. Quote Link to comment Share on other sites More sharing options...
GS Dave Posted February 17, 2014 Report Share Posted February 17, 2014 (edited) PS...Sorry for pulling up an old post....just happy I found out its not just me. ;) Edited February 17, 2014 by GS Dave Quote Link to comment Share on other sites More sharing options...
Braker Posted March 4, 2014 Report Share Posted March 4, 2014 Yes I test drove an F150 with a sunroof once and when I opened the sunroof it did this...also my wife's brand new cx-5 does this really bad when one back window is open. It's a very disorienting sound and is pretty much unbearable for me. Quote Link to comment Share on other sites More sharing options...
Bill-N Posted March 4, 2014 Report Share Posted March 4, 2014 Opening another window will help. I find front and back on the same side works well (when it isn't so darned cold). Quote Link to comment Share on other sites More sharing options...
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