whining, high speed, motor type spinning noise on cold startup

[jcbadger]

Hi all

This only happens on a cold startup. I get a high speed motor type whining noise for a few seconds when I startup then it disappears. There is no such noise during driving or when shutting down. Likewise, once the engine is warm and restarted the noise is not present - it really is just the one time on first cold startup. The alternator belt is fine and I've checked the tension. Could it be the starter motor spinning on but then if it is then why only on cold starting. Likewise if its alternator then surely it would present at every startup regardless of whether the engine is cold or warm. Any ideas please. Thanks

[aw11rally]

Is this noise before the engine starts to turn over or after the engine has started?

It sounds to me like the starter motor gear is not fully engaging or disengaging with the flywheel ring gear.

This can occur due to a build up of dirt in the 'gearbox' of the starter motor.

It may be worth dropping the starter motor (its wedged under the exhaust manifold so this can be a bit of a pain) and giving it a quick strip down and clean. Dirt buildup on the bendix gear is usually the problem as this prevents the pinion from sliding cleanly. I guess this could be affected by temperature due to the differing expansion rates of the materials used.

[jcbadger]

Hi. thanks. its straight after startup and the engine is running.

[aw11rally]

I'd guess its the starter remaining engaged.

[PW@Woodsport]

Can sometimes be caused by a sticking starter relay or faulty ignition switch rather than a faulty starter, worth checking.