Rumble sounding bonk over small road defects.

[raypaice]

My CX-5 started making a small short rumble when going over samll road defects (not large ones) I think it is coming from the front and tapping the front bumper section seems to make the noise. I have replaced some of the plastic rivets to tighten up the fixings but it is still there.

Short of removing the undertray etc I cannot easily see how the front is attached or if anything is loose. Can anyone help?

Thanks

[raypaice]

Having had younger passengers with better ears they say the noise is coming from under the drivers seat. Pointing more to the undertray. Any suggestions to try to stop the noise?

[raypaice]

I think I have identified it now. It appears to be where the bumper undertray and the next undertray meet. The middle is drumming when tapped and looks as if it needs a centre fixing. As soon as I get a free sunny day I will get under and see if a well placed tiewrap helps. Any other ides?

Thanks
Ray

[Willpower]

Sorry that you seem to be getting no responses to your problem. It looks like a one off that nobody else has experienced. Good luck with resolving it.

[Bert321]

Drill holes and fit an extra plastic rivet, or install a piece of foam or something between the two pieces?

[raypaice]

Drill holes and fit an extra plastic rivet, or install a piece of foam or something between the two pieces?

Thanks I have already bought more rivets and plan to get out and under this weekend.

[raypaice]

That wasn't the problem. I have removed the front panel and the two side wheel arch panels looking for anything loose. Re fitted everything added extra plastic removable rivets to anything that looked like it can resonate. Nothing still it makes the noise over my test road.
Small joints in the road surface or rough surfaces create the noise but large bumps do not.

Anyone have any other ideas?

[Willpower]

Personally I would be checking the security of all the bolts and nuts securing engine mounts and things like the radiator mountings.  Anything that is supposed to keep components in place. 

[raypaice]

Thanks Willpower

I have checked and fitted extra rivets to the undertray without success. This week I found the push in top radiator mounting clamps were worn so the top of the radiator was moving about a bit. Took them off lined with sticky back foam (2mm) and refitted and that fixed that. Cannot reach the bottom ones to check as I need to remover the undertray again, so a job for Sunday.

I checked recall service bulletins and checked those but all okay. Everyone who gets in the car points in a different direction when I ask "where do you think that noise is coming from" I still think low front so the radiator is definitely the next thing to check.

I have watched a video on Youtube on how to remove the front bumper to look behind that and check its fixings but despite looking easy I am thinking that's a bit drastic. I just wish I could induce the noise while the car is on the ramps, as no amount of tapping around the front is producing it. So fix something take it for a drive, luckily a road nearby has noise inducing faults, fix it again and ......

I love my CX-5 but this problem is proving frustrating.

[Deeps]

Way back there was a post on the German website in respect of strange noises coming from the front end and although it took an eternity to find the cause the final result was a happy ending. Sorry but I haven't got the time to search through past posts that I have made so I'll leave that to you LOL. Although I cannot now link to the image via Photobucket (refuse to pay their excessive charges for what once was free) which was originally the case I'm still able to access it and so have placed it on another site. The image shows the bolts that work themselves lose after a while. https://imgur.com/a/MrQyH

[raypaice]

Thanks for that Deeps. I think I have seen that post and have already tightened them. Seems lower down thinking lower radiator fixings which I have yet to get to

[raypaice]

I removed the front undertray yesterday and took off the front bumper inner support too. Nothing loose and lower radiator fixings were tight. All refitted and fixings checked. Generally anything plastic has some movement/flex presumably designed for absorbing pedestrians.

Tapping the undertrays makes them drum but I cannot replicate the noise I hear on roads so can only guess this is the case.

Thanks

[Willpower]

Completely out of the ball park, but have you checked the inner side walls of your tyres ?  Sometimes they get a lump/bulge which you cannot see from the outside.  Very easy to check.  Just a thought. 

[raypaice]

I know what you mean and I am sure I would have noticed that the amount of time I spent under the car yesterday :-) It's not really that sort of noise. If you think of Rolf Harris' (sorry to mention him) wobble board, when you shake a sheet of board, its that sort of noise.

Thanks for your input.

[raypaice]

I emailed the Mazda dealer today to see if it is a known problem. Reply was "not sure it's a known problem but book it in for £118 and we will investigate! Mmmmm???