C30 Electrics : Alternator?

[Angrybiker]

Hello guys,

Picked up a 2009 C30 1.6 diesel R-Design for the missus, had just under 80k on clock and had been well looked after. As there was no mention of it in history, dealer offered to change DPF before purchase, so saved a few quid there.

Anyway, last Monday missus phoned and said the car had just died on her, no warnings it just died(luckily round the corner from our house). She locked car up and there it sat till Friday.

I came home, tried to start her but nothing so pulled leads for 10 mins, threw a new battery on her and she fired up straight away. Multimeter was saying running that she was getting 13.2v regardless of revs.

Went out to oulton park yesterday(maybe 2-2.5 hour round trip) she didn't miss a beat yet low and behold this morning, missus drives to work and half way there it dies again.

Battery is measuring 11.2v and she wont turn over.

Bad Alternator?

[cheshired5]

The whole alternator won't be bad so it's more down to how much time you have to suss it out for yourself and replace the part.
Diagnosing is straightforward. Access often isn't.

[Bungo]

If you have a meter you can check alternator output or Halfords do a check.

That was a good deal to get dpf changed. Is it dry or wet, I'd assume a 2009 would be dry.

[JulianT]

If the volts don't go up as you rev from tickover to perhaps 13.8 to 14.2 volts, it's not charging.

Could be a simple fault or a new alternator. Drop it back to the seller.

If you do it yourself, it's not a bad job.

[paddyred]

As said its a simple job to check the alternator. From a healthy electrical system you want to see 12.6V from a battery with no engine running. With the engine running you should see 13.8-14.2V at idle and all the way through the rev range. Regardless of Rev's or loading the voltage shouldn't step out of that range. If you get that then go back into the car and turn on every electrical thing you can, Cabin heater, lights, heated seats, windscreen demister etc and check again. If you have got a between 13.8-14.2 then you should be okay on the alternator front. If not and the bearings in your alternator are okay (i.e. not whining) then instead of replacing the whole thing for a hefty sum you can change the alternator regulator/brush pack for around £35 and save some money.

The thing that confuses me is usually during an electrical issue with the alternator like if it wasn't working then you would get a warning up saying your running on battery and your power steering cuts out. The whole car doesn't usually just shut down and die. A system shut down could be caused by alternator overvoltage and the system voltage protection cuts in. I would say you pretty much definitely have a dodgy alternator though.

[Angrybiker]

Thanks for the replies guys

Originally Posted by cheshired5

Diagnosing is straightforward. Access often isn't.

Yeah, it's pretty tight in there.

Originally Posted by Bungo

If you have a meter you can check alternator output or Halfords do a check.

That was a good deal to get dpf changed. Is it dry or wet, I'd assume a 2009 would be dry.

Checked mate, it's putting out 13.2v running. Not sure on the Wet/dry, the little research I'd done on the C30 it had cropped up they needed looking at around the mileage the car was at.

Originally Posted by JulianT

Could be a simple fault or a new alternator. Drop it back to the seller.

If you do it yourself, it's not a bad job.

Yeah, picked it up a few months ago and the seller to be fair, is a bit of a tit.

I'd read on further research that the alternators were a real weak point on these and possibly an absolute pain, now you guys are telling me they are somewhat serviceable, my wallet is feeling a little more relieved.

Originally Posted by paddyred

As said its a simple job to check the alternator. From a healthy electrical system you want to see 12.6V from a battery with no engine running. With the engine running you should see 13.8-14.2V at idle and all the way through the rev range. Regardless of Rev's or loading the voltage shouldn't step out of that range. If you get that then go back into the car and turn on every electrical thing you can, Cabin heater, lights, heated seats, windscreen demister etc and check again. If you have got a between 13.8-14.2 then you should be okay on the alternator front. If not and the bearings in your alternator are okay (i.e. not whining) then instead of replacing the whole thing for a hefty sum you can change the alternator regulator/brush pack for around £35 and save some money.

Thank you, Battery was brand new and checked out at good voltage when I replaced it, that's why I leant towards alternator fault.

I'll dig around and see if I can hear any unusual noises, there is an ever so slight turbo whine, is the Alt bearing whine more noticeable than that? or is it a stethoscope job?

I'll also be looking into the Reg/brush pack, thank you for that.

Originally Posted by paddyred

The thing that confuses me is usually during an electrical issue with the alternator like if it wasn't working then you would get a warning up saying your running on battery and your power steering cuts out. The whole car doesn't usually just shut down and die. A system shut down could be caused by alternator overvoltage and the system voltage protection cuts in. I would say you pretty much definitely have a dodgy alternator though.

She did say the power steering dropped out a moment before it died(the second time) with new battery. The old battery was shot, it measured some 6 volts when I checked. I'm guessing it was weak anyway and maybe a cell dropped out causing it to lose voltage so quickly the car didn't have chance to drop things out individually to power save.

Thanks again guys.

[paddyred]

No problem, cheapest thing for you to do now is to pull the alternator out and change the brush/regulator pack. Well an alternator whine is noticeable, you know the sound a gearbox makes when its given up the ghost? Its nearly identical to that and pretty loud usually but you can hear it when parked and it will change in pitch with the RPM.