djc Posted June 9, 2015 Report Share Posted June 9, 2015 I am owner since April of a 2013 C-max with 26,000 miles. Shortly after buying the car I experienced a loud moaning-groaning noise under part-load conditions (acceleration or ascending a hill). The noise would diminish if I either let up on the throttle or used heavier throttle. Speed also seems to matter - seems loudest between 20 and 40 mph. Noise appears to be coming from passenger footwell. There is a TSB for the noise. The official remedy for the "concern" is to check the noise-cancelling audio system. I have the impression from forum discussion that this does not generally fix the problem. I have run the first bit of the remedy myself (running a self-check on the speakers). Also it is clear it doesn't get to the source of the noise, it simply tries to mask it. In any case, I haven't noticed the noise in the past couple weeks as temps have risen into the 70s here. So I am wondering if this problem is temp sensitive, and whether the noise is seasonal or affects only cars in colder places? And of course I am curious if anyone has a theory as to what actually causes the noise (seems to be a panel vibrating, and seems to be on right side, so engine related)? Ephethean3 1 Quote Link to comment Share on other sites More sharing options...
Podivin Posted June 9, 2015 Report Share Posted June 9, 2015 On my car it's 'seasonal' only insofar as it only happens when I've got windows down.Apparently the extra noise from having the windows down somehow confuses the noise-cancelling system and it activates when it doesn't need to be (or it SHOULD be working, but having the windows down changes the acoustics in the car enough that we can hear the sound the noise-cancelling system makes).In any case, in my car I only hear it with the windows down.It would have been nice if Ford had given us the option to turn that feature off without having to remove a fuse, which disables other things also. Quote Link to comment Share on other sites More sharing options...
djc Posted June 9, 2015 Author Report Share Posted June 9, 2015 Podivin, I think that's a different exciting noise, with its own TSB. Mine is definitely an "all-windows-closed" (cold weather) noise, and at lower speeds. I've heard a buffeting noise in other cars when windows are down at certain speeds - seems to be basic physics: at speed with windows (partially?) open the car acts like a beer bottle with someone blowing across the open end. Perhaps the Ford noise-canceling system can make it worse under certain circumstances. The other noise is at relatively low-speeds with all windows up - and is more alarming. Quote Link to comment Share on other sites More sharing options...
Podivin Posted June 9, 2015 Report Share Posted June 9, 2015 Gotcha, it's not surprising this is a different noise (we seem to have plenty to choose from).This isn't the usual buffeting noise, this is a big bass note coming from the speakers, at certain speeds and accelerations.For me it's not worth taking it to Ford for any sort of update, it happens rarely, and if I don't want to hear it I can simply put up the windows. :) Quote Link to comment Share on other sites More sharing options...
bigalpha Posted June 10, 2015 Report Share Posted June 10, 2015 Does it sound kind of like a bad wheel bearing? May be bad transmission. Take it to the dealer for insepction. Quote Link to comment Share on other sites More sharing options...
John Sparks Posted June 11, 2015 Report Share Posted June 11, 2015 There's another thread about the same noise. The link is below. Anyway it's a load related, harmonic vibration. It's completely normal. Mine has been doing it since day 1 and I have over 46,000 miles on it now. http://fordcmaxhybridforum.com/topic/5049-2013-sel-loud-noise-while-accelerating/?view=getnewpost Quote Link to comment Share on other sites More sharing options...
scottwood2 Posted June 11, 2015 Report Share Posted June 11, 2015 There's another thread about the same noise. The link is below. Anyway it's a load related, harmonic vibration. It's completely normal. Mine has been doing it since day 1 and I have over 46,000 miles on it now. http://fordcmaxhybridforum.com/topic/5049-2013-sel-loud-noise-while-accelerating/?view=getnewpostMine has been doing this also but I feel that harmonic vibration is very damaging and I try to change my accelerator position to make this go away. Some said it has to do with the noise canceling system in the car. Either way I like to do what I can to keep it from happening. It does not take much for it to be gone. Quote Link to comment Share on other sites More sharing options...
djc Posted June 12, 2015 Author Report Share Posted June 12, 2015 To me it does sound like a harmonic vibration - some body panel caused to vibrate by something. Given the noise seems to come from the right side of the car, I am thinking the engine. I tried googling to find out the location of the engine mounts with no luck. Working hypothesis number 1 is: there's an upper engine mount on the firewall. Backup hypothesis two: it seems there's a TSB for replacing the right fender liner if there is excess noise from the airconditioner. So maybe that large surface can vibrate with the AC. Why not the engine also? (Aside - in hunting for engine mount info online, I did come across parts price lists. High volt battery is expensive, of course. Surprise was the AC compressor at over $800. Ouch. ) Since I haven't noticed the noise since temps have risen while driving the same routes, another hypothesis is that thermal expansion changes the properties of whatever makes the noise (could be elastic material in the engine mount, could be the vibrating panel). The temp hypothesis would get a small bump in confirmation if anyone else has noticed the noise goes away as temps rise (or starts when they fall) or b) has never experienced the noise and lives in a warm place. It would be disconfirmed by those who experience the noise no matter what the temp. It would be useful, in tracking down the cause, to hear from more owners about the effect, if any, of temperature on this noise. Quote Link to comment Share on other sites More sharing options...
Bill-N Posted June 12, 2015 Report Share Posted June 12, 2015 It may or may not be relevant, but I hear a slight engine-knock sound under light load. I drove another C-Max and it made the same sound so I believe what I'm hearing is normal. Since Atkinson-cycle engines have high compression ratios (compared to "regular" engines) they tend to make a diesel-like noise under load. That's my theory. Quote Link to comment Share on other sites More sharing options...
John Sparks Posted June 13, 2015 Report Share Posted June 13, 2015 (edited) Mine will do it any time of the year but I'm telling you, it's completely normal. I'm a Ford sales rep. I've driven 2 dozen different ones and they all do it. The average driver who does not drive for mileage will likely never hear this noise. It's a specific load generated sound. You also have to realize this thing functions quite different than a traditional ICE. There's a plethora of sounds it will make and different operating characteristics altogether. Now granted the sound is not a pleasing one but, it is easy to quickly remedy by speeding up or letting off the accelerator. As far as the fender liner. I haven't heard of this TSB. I can tell you the inner liner is nothing more that a sound dampening material. It plays more of a part in dampening road noise than engine compartment / AC Compressor noise, though I don't doubt it will help some. Edited June 13, 2015 by John Sparks Quote Link to comment Share on other sites More sharing options...
Bill-N Posted June 13, 2015 Report Share Posted June 13, 2015 It's TSB 14-0073. http://fordcmaxhybridforum.com/topic/4804-tsb-14-0073-air-conditioning-ac-compressor-noise-heard-inside-the-vehicle-cabin/?hl=14-0073 Quote Link to comment Share on other sites More sharing options...
nsteblay Posted June 17, 2015 Report Share Posted June 17, 2015 I've heard the noise occasionally. I've always considered it part of normal acceleration. I do believe you get more sensitive to car noises in the C-Max because it often runs silently. Quote Link to comment Share on other sites More sharing options...
djc Posted June 19, 2015 Author Report Share Posted June 19, 2015 Thanks for feedback.I am convinced the noise is normal - for a C-max. I would like to know what causes it. After not hearing it for a couple weeks, I did hear the noise again twice yesterday. Both times going up hill. Much more subdued than in colder weather. Ambient at the time of the noise was 63°, cooler than it has been. I looked under the hood and 2 engine mounts are very obvious. There may be another on the engine back; that might not support much weight but would resist twisting under load and might connect near middle of firewall, where engine and trans bolt together. The big left engine mount has 3 bolts to the engine and a couple of bolts to the body (easy to see it - high, in front of the strut tower, just above left axle). This left mount appears to be an inverted metal cup over a rubber material. It would not be surprising if its vibration isolation properties are temperature dependent. Also it seems to have been changed in Feb 2013, perhaps to improve its vibration isolation.picture here:http://www.fordparts.com/Commerce/PartDetail.aspx?n=jIef1CVUv3oazjdbLR0rKw%3d%3d&id=318519562&m=2&search=true&year=2013&make=Ford&model=C-Max(click diagram at left to enlarge). As temps fall in Autumn I may use a mic to try to pin-point source, but I am hoping a summer Ford TSB will appear that makes it go away! d. Quote Link to comment Share on other sites More sharing options...
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