Alternator gremlins

[E_T_V]

Grr why does my car have to go wrong after the sunny weekend where I had time to fix it? Driving to the car repair shop today I was greeted by a fair bit of alternator whine on the radio. This isn't massivly unsual as I've been trying to get rid of it for a while now. However once I reached my destination I turned the engine off and the battery charge light came on. When I turn the ignition on the light goes off and it remains off when the engine is started.

When the voltage was measured it is charging but only just, i.e. 13.0v rather than 13.5-14 etc. I'm hoping that the voltage regulator and brush pack has packed up rather than the diodes inside the alternator as the brush pack is easily replacable and I have a spare new one kicking about.

Any other ideas that I've not thought about because I'm too busy?
I checked for a sticking relay by pulling out and replacing the relays in the fuse box one by one but I didn't feel any of the click and the battery light remained on all the time.

I've unplugged the alt for now to stop it draining the battery.

Grr flamin campervan. I gave it an oilchange this weekend too and this is how it repays me!

[ben rawlings]

we had this on our maestro td when we first got it.

have you tried unplugging the alternator wires and cleaning the conectors because as far as i can remember the alternator is quite low down in the engine bay. the connectors tend to accumulate alot of crap etc off the road.

[E_T_V]

Hmm yes it is in rather a crud catching position. I've unplugged and plugged it back in a few times (it is the plug type conenctor rather than the ring terminal ones), but improvement. I have to admit I did think the battery light was a bit dim when the ignition was on a few weeks ago. Perhaps it has finally bitten the dust/crud?!

[tony]

the diode has gone , its time for a replacement alternator. the battery is feeding back thro the alternator and then up the ignition light .

[E_T_V]

Yes that was what I feared and proved tonight by substituting the regulator/brush pack. Oh well time to go get a new one. :( I suppose it hasn't done that bad really seeing as it now has 210+k miles on it

[ben rawlings]

thats a fair few miles on the same altinator.

[Rich]

I am pretty sure the diodes are in the brush pack itself, not in the alternator part. If not I am sure you could replace them, if you can get some from RS etc, they must just solder in somewhere, no doubt making up a bridge rectifier to convert the alternotors AC in to DC.

If the bearings in the alternator are noisy, it may be worth getting an exchange unit? Anyway try the brush pack first, i'm sure that will clinch it, if not you can always keep it as a spare.

Rich

[E_T_V]

I've already changed the brush pack as it is so quick and easy to change and I had a spare new one lying around however no change in the results. The diodes are buried in the main alternator unit itself so it would have to be stripped to be repaired and for the sake of £40 I'll get an exchange one. The bearings are fine and everything appears ok apart from the lack of charge and the drain when the engine is off. I fitted the alternator from my old diesel engine rather than the newer one that came with my TD engine as the loom has different wiring connectors, i.e. it has a plug rather than the ring connectors and the newer alt only had ring connectors on it and I didn't want to butcher my wiring loom. Ahh well lets hope the exchange one has the plug in connector on it.

Interestingly enough when I asked for a price at my local motorfactor they tried to quote me for a 55amp alt as that is all their book listed. I managed to get them to quote me for a 65amp one in the end but just as a note to anyone in a similar situation I thought that all 2 litre Monty and maestros had 65 amp alternators whilst al the others had 55amp ones (apart from police spec 1.3's which have 65amp ones).

[E_T_V]

Hmm a new an interesting quirk to proceedings has just occurred. Previously with the igniton off I got the alt light on. With the igniton on it went off and remained off when I started the engine.

This morning when I plugged the alt back in (I've been leaving it unplugged overnight so as not to discharge my battery) with the igniton off the light remained off. With the igniton on it comes on as it should do and when you start the engine it glows faintly until you rev the engine when its brightness increases. I know the unit is knackered but this is a new and interesting twist to the tale!

At least I've got a big battery so it hasn't gone flat yet!

[e692wtt]

I think the alternator is talking to you... something like change me sooner rather than later I reckon :laugh: .

Seriously, I don't think you'll get many more miles out of it... it deserves a rest at 210,000 miles I'd say.

[E_T_V]

I just picked up a new one today. 65Amps for the gand sum of £45 plus a fiver surcharge until I return my old one. I guess I've had my moneys worth out of the old one I suppose :D

I just hope it doesn't turn out to be a wiring fault or a dodgy relay somewhere! I guess we'll soon see.