Car has started making a loud wheezing or sneezing noise on cold starts from under the hood.

The noise occurs once and lasts for about 1 second. It sounds a bit like a belt slipping, or like a tyre slipping on a wet road, except more grinding, coarser and more metallic. It's quite loud.

So far it only happens on cold, rainy days (although doubtful that the rain is causing it).

There are no other noises and the car drives perfectly fine after this.

Any ideas? I had thought starter motor, but if the starter motor was bad it wouldn't just happening on cold starts, right?

2000 AP1.

 

Try searching for 'air pump' Theres a system on the s2000 which acts I suppose as a EGR. It happens only on cold starts and there have been instances where they have started to fail.

 

Hmm, most people report a whining, turbo like noise when the air pump fails.

My noise seems to be harsher, more metallic and almost violent. Like I imagine starting an engine with no oil in it would sound.

 

Did some more research and tending to think it's starter over-run, which is apparently quite common? I'd never heard it before in this car, but I guess this is the first really cold weather I've had the car in.

General opinion is it's harmless and there's no point fixing it.

 

Most likely metallic cold start noise is a timing chain tensioner.

The air pump will run at cold start normally but it is much higher pitched than a noisy tensioner. Videos have been posted repeatedly.

 

Do you think it could be the serpentine belt getting old?

 

Can you make a vid and post it so we can hear?

 

The symptoms seem to match the description for start over-run in this thread

https://www.s2ki.com/forums/index.php?showt...&#entry14469840

It could be TCT, but I don't understand why that would make a very brief noise and then stop completely. Also, why would TCT noise only happen when cold?

Serpentine belt is a possibility... how do i check that?

 

Try spraying some water on the belt. This works best with a soapy solution for added lubrication but just plain water should at least change the character of the noise, if not eliminate it completely.

 

Had this problem bout a year ago, its a loud screech happens for a sec when the car has been sitting for a while with the temperature being below 60. The sound your hearing is friction between the bendix gear on the starter and the flywheel. Resolve is either rebuild starter with new bendix gear or a new starter which is the way I went. Took me and a buddy a half hour. Dont delay the repair as over time you will start breaking teeth off the flywheel and then shit really hits the fan. Later Marcus.