I thought I'd share this, really just for info.
It turns out that on my 2018 Multijet Panda, the pulley on the alternator that the drive belt runs over is of the freewheeling type, designed to uncouple the drive at certain times (eg sudden lift-off of the throttle) to prevent the belt from being stressed and to make everything smoother. This may apply to the TA engines too?
For a while now (maybe a year), after driving through some deep flood water, the alternator has tended to whine. Briefly - a few days - after going through that floodwater, the alternator would occasionally make a noise like a dry bearing, but this went away, although a constant 'hum' remained. More recently, on starting the car, the engine would initially idle smoothly but then start 'hunting' (the revs rising and and falling in a pulsing way, a bit like the way a lawnmower does). And, on turning the engine off (or the stop/start stopping it), there was a sort of 'sigh' as the alternator slowed and stopped.
I knew it needed attention but have been putting it off as all was still working, just not sounding as sweet as it should.
Yesterday, returning to Hertfordshire from North Norfolk, through biblical rain and unavoidable shallow floods of sandy/muddy runoff from the local fields, the alternator drive again started to whine loudly. But again, after a few miles more it was back to 'just' humming and apparently al was well(ish).
However, as we headed south, the battery light came on (showing the alternator was not charging it), initially just briefly, now and again, but gradually staying on for longer each time as teh alternator drive failed further, and the car started to go through the list of all the warnings it shows as the voltage drops (in passing, confirming my long-held view that these warnings are nearly always linked to voltage drops rather than actual parts failing)... in order: ESC/Hillholder not available; later, 4x4 mode unavailable. Then, as we continued the 100 mile trip various other messages including about loss of ABS, airbag system, Power Steering, Fuel Cut off and finally 'Check engine'. Each accompanied by a growing Christmas Tree of lights. Frustratingly, less than a mile from home, the last electrical item still functioning - the fuel pump - cut out as the battery finally gave up. I had hoped to nurse it all the way, and fell just short after 99 miles. Britannia Rescue jump started it to drive up onto the recovery truck and got me to a local garage where hopefully it will be fixed in a couple of days.
And what's failed? Well, quite simply that freewheeling clutch on the pulley (for example and explanation , see here https://idpartsblog.com/2018/07/09/clutched-alternator-pulleys-are-important/ [edited - a better link inserted] ). I speculate that it has failed in a way that means it's not driving the alternator at all: initially harmed by sand in the works a year ago wearing away part of the clutch system, and finally failing fully during the drive yesterday. The pulley is a separate part and can (in theory) be removed with the alternator in situ (there's a special tool that holds the works still while you unscrew the pulley from its spindle.)
I'll keep you posted
It turns out that on my 2018 Multijet Panda, the pulley on the alternator that the drive belt runs over is of the freewheeling type, designed to uncouple the drive at certain times (eg sudden lift-off of the throttle) to prevent the belt from being stressed and to make everything smoother. This may apply to the TA engines too?
For a while now (maybe a year), after driving through some deep flood water, the alternator has tended to whine. Briefly - a few days - after going through that floodwater, the alternator would occasionally make a noise like a dry bearing, but this went away, although a constant 'hum' remained. More recently, on starting the car, the engine would initially idle smoothly but then start 'hunting' (the revs rising and and falling in a pulsing way, a bit like the way a lawnmower does). And, on turning the engine off (or the stop/start stopping it), there was a sort of 'sigh' as the alternator slowed and stopped.
I knew it needed attention but have been putting it off as all was still working, just not sounding as sweet as it should.
Yesterday, returning to Hertfordshire from North Norfolk, through biblical rain and unavoidable shallow floods of sandy/muddy runoff from the local fields, the alternator drive again started to whine loudly. But again, after a few miles more it was back to 'just' humming and apparently al was well(ish).
However, as we headed south, the battery light came on (showing the alternator was not charging it), initially just briefly, now and again, but gradually staying on for longer each time as teh alternator drive failed further, and the car started to go through the list of all the warnings it shows as the voltage drops (in passing, confirming my long-held view that these warnings are nearly always linked to voltage drops rather than actual parts failing)... in order: ESC/Hillholder not available; later, 4x4 mode unavailable. Then, as we continued the 100 mile trip various other messages including about loss of ABS, airbag system, Power Steering, Fuel Cut off and finally 'Check engine'. Each accompanied by a growing Christmas Tree of lights. Frustratingly, less than a mile from home, the last electrical item still functioning - the fuel pump - cut out as the battery finally gave up. I had hoped to nurse it all the way, and fell just short after 99 miles. Britannia Rescue jump started it to drive up onto the recovery truck and got me to a local garage where hopefully it will be fixed in a couple of days.
And what's failed? Well, quite simply that freewheeling clutch on the pulley (for example and explanation , see here https://idpartsblog.com/2018/07/09/clutched-alternator-pulleys-are-important/ [edited - a better link inserted] ). I speculate that it has failed in a way that means it's not driving the alternator at all: initially harmed by sand in the works a year ago wearing away part of the clutch system, and finally failing fully during the drive yesterday. The pulley is a separate part and can (in theory) be removed with the alternator in situ (there's a special tool that holds the works still while you unscrew the pulley from its spindle.)
I'll keep you posted
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