Mazda 323 Timing Belt Replacement - Noise

Hi all, long time reader, first time post.
I've just had a timing belt replaced in my 2001 Mazda 323 and the car has gone from being relatively quiet under the bonnet with nothing of concern, to now having a noticeable whine sound with a slight whistle noise.
I only replaced the timing belt as it was due, the car has been driving well (and still seems to be driving well since the timing belt replacement).
Now I've handed over the cash, driven away, and I don't know whether a noise such as this from under the bonnet is something that I should be worried about?
Any thoughts or advice?


  • They have probably fitted the timing belt covers incorrectly, the belt or a pulley is possibly rubbing on the plastic cover. Take it back and tell them to fix it.

  • Without hearing anything, if its a sort of high pitched whine it could be the water pump. Post a video of the noise, as it would probably help a lot more in diagnosing it.

  • Whatever it is, if it wasn't there before, it shouldn't be there now. Ask them to take a look.

    BTW, how much did it cost. Our 2000 model 323 is due. It looks fine but is 10 years old.

    • It cost me $505 for the timing belt kit. I received quotes from a few mechanics anywhere up to $750. As always I got a phone call mid-afternoon re a few other odds and ends that needed to be done and it cost me just over $800 total.

      Now that I’ve read a comment here about the water pump being a possible noise source, I’ve done some googling and perhaps the water pump should have been done at the same time as the timing belt. Something to consider in your quote.

  • Does it sound like this?

    You might have gained some hrsprs too.

  • Just take it back and get them to look at it. Could be any number of things, related or unrelated to the work done.
    Hopefully it's just a drive belt/pulley making the noise.

  • Get it back to them asap. Call them first and ask if they think it is worth the risk driving it to them? They might want to come and look first in case it creates expensive damage.

  • The most likely cause is the timing belt has been adjusted/set too tight.
    It causes a whining or whistling sound when the belt has too much tension on it.

    Take it back for inspection.

  • A whine would indicate the belt may be slightly too tight. Address the issue by asking the person who replaced the timing belt, it’s not a big job to adjust the tension

  • Thanks for your replies. I contacted the mechanic (with a little more confidence to do so thanks to your replies here) and I took it back in for them to adjust. Seems to be Ok now, fingers crossed.