Diff noise?

[Simonc5150]

Hi guys

This is my first post here, I could really do with your advice.

I've got a 2007 MX5 Sport and recently I've noticed that the noise inside the cabin has become quite loud! It's definitely mechanical in some way as the volume and pitch is relative to road speed. I think it's independent of the engine though as it sounds like it's coming from the rear of the car and taking it out of gear while driving along doesn't affect the sound. It sounds like a fairly low sounding grinding noise.

Can I ask if you have any recommendations on how to diagnose the problem? Could it be the diff?

Thanks in advance
Simon

[binarypunk]

It could be...or more likely a wheel bearing.

The way to work it out is to jack it up, spin the wheels and see where it is coming from.

[Mazda Mender]

I would look at the wheel bearings first also before the diff buddy

Oh and greetings and Simon ,lets see some pics of your pride and joy....
M-m

[flea]

Welcome to Menders

[Simonc5150]

Okay great..Hopefully it's not the diff as that sounds like it would be way more expensive to fix!

Thanks for your advice so far :) Unfortunately I've got zero tools and equipment to check anything so will need to find somewhere good to take it. I live in Manchester, any recommendations?

I'll get some good snaps and post them up soon - I've had it about 6 months and have loved every second so far. I've wanted one for years and it's everything I expected and more so far! :)

[pollyanna]

Have you tried getting it up to the speed that makes it the noisiest, then put the gear into neutral and switch the engine off to see if it is engine related or not. Caution don't turn the ignition key all the way as you will lock the steering wheel and you will also lose the power steering , if fitted. So you need to be on a straight piece road with not many other cars about. I guess this might be difficult where you live tho'.

Noises in this car are difficult to find as the cause could be coming from somewhere other than where you think it is. A wheel bearing going usually gives a regular whineing sound that changes tone a bit, the faster you go.
As previously said jack the car up and see if you can feel anything that is other than very smooth.

[Mazda Mender]

You are more than welcome to pop up and let me have a look and listen.
M-m

[Simonc5150]

Thanks for the advice - i'll give the engine switch off trick a go. I'm pretty sure it's not coming from the engine, I suppose it kind of sounds like a flat tyre or something (it's not - i've checked!!) . Lots of road noise and like something is finding a lot of resistance when spinning.

Wayne - I think I may just take you up on that offer. Whereabouts are you based?

[Mazda Mender]

Pie land
M-m

[Lazza]

Check your tyre pressures too as low pressure can mean more tyre noise. How badly worn are your tyres and have you checked for wheel and/or tyre damage?

[Simonc5150]

I just had a look at the tyres - they're all okay except bizarrely the front two were at 22PSI! I've inflated and the noise is still there. I also tried the engine switch off test and the sound is there all the time, independent of the engine.

The noise diminishes depending on if I take a left or right hander. In straight lines, it's always there. Does that sound like bearings?

[Mazda Mender]

It does sound like a bearing
M-m

[Lazza]

Yep, bearings. At least you now have the correct tyre pressures (should be 26-28psi).

[Simonc5150]

At least now I know! Thanks.

It does seem a little odd at at 42k A wheel bearing it two has gone. Is that normal? I've seen a few kits online - is there no hub for rear wheels? Is that just for the fronts? Does it matter where I get the bearings from?

[Mazda Mender]

Give Andrew a ring at Autolink
M-m