Mazda CX-3 Forums

My CX3 has just started to make the most horrendous rattle when accelerating out of low revs. It’s coming from the front passenger side of the car and sounds like it’s underneath but I’ve had it looked at by a local garage for anything loose and they couldn’t find a problem at all after suspecting it could have been a loose heat shield. Has anyone else experienced this? My car is 4 1/2 years old but sounds like it’s 14 years old when that rattle occurres. Yes I’ve had people say just change down gear but it never made this sound until a few weeks ago so it’s not normal for the car plus it doesn’t make that sounds if I’m in low revs and slightly in a curve, it only does it when driving in a straight line. Does anyone have any idea what it could be?

Could it be the passenger seat belt buckle rattling on the B pillar?

The passenger seat can rattle on its rails too. If you push sideways on the seat when you hear the rattle and it stops, there's your issue. I wedged some black foam down between the seat and the centre console which fixed it for me.

jtonline wrote: ↑Thu Jun 24, 2021 10:07 am The passenger seat can rattle on its rails too. If you push sideways on the seat when you hear the rattle and it stops, there's your issue. I wedged some black foam down between the seat and the centre console which fixed it for me.

Hi, it really sounds like it’s coming from outside the car and underneath at the front passenger side, it’s definitely not inside the car.

Stagman wrote: ↑Wed Jun 23, 2021 9:02 pm Could it be the passenger seat belt buckle rattling on the B pillar?

Pretty sure it’s coming from outside the car and underneath on the passenger side.

I think you'll need to take it back to a garage and get them to do a test drive and diagnose the issue.
https://autochimps.com/car-rattling-noise-accelerating/

What was the outcome of both 'Wobbly car' and 'Engine shaking violently' that you posted about earlier?

Dont know if this will help, but........
I have a similar rattle coming from the nearside front passenger seat. I traced this to the plastic cover that goes over the lever that adjusts the seat back position. Its was supposed to be fixed at the last service, but its still there! Its worse when going over bumps in the road, but I think, because the 2 litre engine is high revving, its more noticeable.

Beezageoff wrote: ↑Sun Jun 27, 2021 4:07 pm Dont know if this will help, but........
I have a similar rattle coming from the nearside front passenger seat. I traced this to the plastic cover that goes over the lever that adjusts the seat back position. Its was supposed to be fixed at the last service, but its still there! Its worse when going over bumps in the road, but I think, because the 2 litre engine is high revving, its more noticeable.

It’s absolutely coming from outside the car, the noise is around the passenger side front wheel of the car or that side of the engine.

jtonline wrote: ↑Sat Jun 26, 2021 10:39 am I think you'll need to take it back to a garage and get them to do a test drive and diagnose the issue.
https://autochimps.com/car-rattling-noise-accelerating/

What was the outcome of both 'Wobbly car' and 'Engine shaking violently' that you posted about earlier?

They took it for a test drive and thought it was a broken heat shield but when they had a look they couldn’t find anything wrong underneath it.
The engine shaking only happens if I start the car on a really cold morning and attempt to drive straight off, if I sit for 30-60 seconds before moving it doesn’t do it.
It’s still a wobbly car, incredibly bouncy, I wouldn’t want someone in it that suffers car sickness because they wouldn’t stand chance.

So after 2 garage visits that found nothing wrong at all I’ve just had it serviced and it no longer makes that noise….. go figure. I still believe it was something to do with when I had 2 new front tyres and something not being put back correctly at the time. I shall probably never know what it was I just hope it doesn’t do it again.