2005Nc noise problem diagnosed as alternator bearings,ques?

rhyde · Postby **rhyde** » Wed Dec 03, 2014 6:32 pm

So from the last thread i started for questions regarding mx5 factory
well i took the car there and Dick was just awesome, lovely guy

he diagnosed my funny engine sound as alternator bearings gone, so it needs replacing

1200 new from mazda
or 400 for a bosch one..
dick said its exactly the same so no prob, go the latter.
however repco say bosch dont do one for thr nc mazda

so what alternators have people used and how much were they?

i can get one from automotive plus second hand for 150?

should i go second hand option, as money is very tight cos i just ordered headers for my car

pezchops · Postby **pezchops** » Wed Dec 03, 2014 7:32 pm

if it was me i would buy the part from automotive plus .
i presume fitting is extra ,or you fit it yourself?
they would give some sort of warranty and its not like if it fails you are going to run off the road and up a tree
if you get to keep the original, you can take it apart and try fixing it ..bearings are cheap if they are a common size

Mr Morlock · Postby **Mr Morlock** » Wed Dec 03, 2014 9:05 pm

You need to do some more homework. Auto electrics guys will know where to source product and whether replacement of bearings is an option. Secondhand parts often have a very limited guarantee e.g. 3 mths though it is an option well worth considering. I would also check with Bursons to see if they list a replacement for oem. There are a number of recyclers around e.g. Allmaz may be able to help.

Sailor · Postby **Sailor** » Wed Dec 03, 2014 10:19 pm

Are you sure?
Tensioner idler failing sounds a lot like an alternator

JBT · Postby **JBT** » Wed Dec 03, 2014 10:38 pm

I tend to agree with Sailor.
My NC has done 92,000km. Still on the original alternator but the serpentine belt tensioner and idler have been replaced due clattering noise.
I don't think I've ever heard of an NC alternator having failed bearings - doesn't mean to say yours haven't of course.

rhyde · Postby **rhyde** » Wed Dec 03, 2014 11:39 pm

Sailor wrote:Are you sure?
Tensioner idler failing sounds a lot like an alternator

yep your right there as well
the mx5 factory said to replace that as well
but thats only 100 bucks, so im doing as that as welll

rhyde · Postby **rhyde** » Wed Dec 03, 2014 11:41 pm

JBT wrote:I tend to agree with Sailor.
My NC has done 92,000km. Still on the original alternator but the serpentine belt tensioner and idler have been replaced due clattering noise.
I don't think I've ever heard of an NC alternator having failed bearings - doesn't mean to say yours haven't of course.

thats the sound i have exactly "clattering noise"

i might just double check with Dick and ask him if if could be just those instead of the alternator

i only have 70kms on my nc

thanks guys u all rock

Regie · Postby **Regie** » Thu Dec 04, 2014 7:58 am

my tensioner has been making a noise for some time now, i haven't replaced it....one day i will

Sailor · Postby **Sailor** » Thu Dec 04, 2014 9:12 am

Mine works overtime so I went looking and found a replacement that doesn't cost a bomb and has a bigger bearing.
It's fractionally larger dia but still fits the accessory belt easily
I was truly surprised at how much quieter the engine sounded and the bearing was only just perceptibly worn

Charlie Brown · Postby **Charlie Brown** » Thu Dec 04, 2014 1:14 pm

I too doubt that it will be the alternator bearings.

The idler pulley became noisy on mine at around 180K. Swapped it (about $40) out and no more noise.

There's plenty of information in the technical section and on Miata.net on how to do the work. Takes all of 10 minutes to do it.

I threw my old one out so I can't give you the bearing number but if you take the old one out and head off to your National bearing shop with it they'll match it.

rhyde · Postby **rhyde** » Fri Dec 05, 2014 9:29 am

Charlie Brown wrote:I too doubt that it will be the alternator bearings.

The idler pulley became noisy on mine at around 180K. Swapped it (about $40) out and no more noise.

There's plenty of information in the technical section and on Miata.net on how to do the work. Takes all of 10 minutes to do it.

I threw my old one out so I can't give you the bearing number but if you take the old one out and head off to your National bearing shop with it they'll match it.

aparantly these alternators cant be repaired as they aint like the old na or nb units ive been told,
automotive plus in brisbane confirmed this too

so im not really sure what to do.

i decided to just go fro a second hand unit and take the gamble. Dick said to me that he wasnt sure at this stage as my car will be ready monday that if the nc has the same pully as nb he would just give it to me for free.. if he had to order it well then lol not for free

overall so far i have found that Dick from the mx5 faxctory is a real gentleman and very accomodating. great guy.

if my car blows up afterwards well then ill say other wise lol