volts drop

[pacman67]

The previous keeper told me he changed the alternator clutch as a preventative measure having heard of issues. Tbh after loosing my job paying for an alternator is something I can do without.

[TXC]

As a quick test/assessment, repeat your idle-rev-overrun voltage test,

only this time use the throttle pedal to bring the engine speed back to idle slowly (a controlled deceleration if you like), if the voltage stays at a more promising level (13v+) then I think you are looking at a pulley failure to be honest, yes it has been replaced in the past, but an aftermarket pulley kit (or genuine for that matter) just will never be as long lasting as a newly assembled unit. (replaced as preventative maintenance? not likely).

The alternator is clearly capable of providing positive voltage, its the overrun period where it (possibly) is slowing to below idle rotation speed - then recovering.

Of course its worth loading the system at idle with some heated screens etc to test the output is capable of maintaining etc

The pulley could of course be loosening , its already been apart once.

If you cant be sure and you can't afford the component/work, then give it a whack and carry on using it just don't commit to any mammoth journeys.

Just my thoughts.

Good luck.

P.S if you do find the funds like Kira, I'd be replacing the whole unit if you've done age related mileage, I did with mine as I couldn't guarantee the pulley/bearings/brushes at 150k, search TXCVOLVO1 on you tube for my vid on aaccessing the unit, it may help.

[Eddy10]

I also have the same kind of problem but also i have a noise coming from the side of alternator, i thought it was the power steering pump changed it and no result, then changed the aux belt tensioner no result so after reading this thought that could the alternator clutch wheel be the problem or it something with the alternator inside ?