Using the Mazda today I have noticed a mid pitched “mechanical” whirring noise from the alternator when the ignition is switched to the first position. When I then turn the ignition further the car starts without a problem and with the engine noise it’s impossible to tell if the whirring noise has gone or not. Checking a second time there was also a second noise that sounded more “electronic” also from the alternator. Again this prior to the engine starting.

There a lot of stuff online about noisy running alternators but nothing very clear about noises before start. I will book it into the garage next week but it may be a few days before they can look at it as I know they have a lot on. We will try to avoid using it meantime but am I worrying unnecessarily, do all ageing alternators make noises and it’s just that I have never noticed before?