Alternator Question

6Sabre · Nov 15, 2020

Hi, I suspect my alternator has a fault.
I can hear a 'hum/buzzing' which appears to be the alternator. (2004 TD4 Automatic)
Has anyone had this or know of the issue. My battery is going flat over a few days, so I suspect it is the issue but at circa £120 I would like to get some confidence it is that.

I have just done brake master cylinder, wheel cylinders, rebuilt the high pressure pump and flushed the auto ( I suspect a dummo garage filled it with the wrong oil giving me the issue in the first place ) I asked for a preventative oil change!!)
The auto still 'thuds' changing gear when cold even with n402 in it, so getting to the point of value re costs etc.
Cheers
Steve

andyfreelandy · Nov 15, 2020

Stick a voltmeter on the battery, read about 11.5 to 12 volts.

Start engine, voltage should rise to 13.4 volts or thereabouts.

If voltage doesn't go up then battery is not charging.
Could be connections, but the noise on the alternator sounds like the brushes have worn down or commutator has worn through. Repair is possible but check it out first and report back!!

6Sabre · Nov 15, 2020

Thanks AndyFreeLandy. I am afraid I was not clear enough. The noise is when the engine is turned off and ignition off and car locked/unlocked
Its not an noise in use.

andyfreelandy · Nov 15, 2020

That's an odd one!!! I'd check it works first, maybe sommat frying inside draining battery!?!

Nodge68 · Nov 15, 2020

6Sabre said:
The noise is when the engine is turned off and ignition off and car locked/unlocked

Does the car have a FBH? Is there a noise coming from the front LH side?

6Sabre · Nov 19, 2020

Nodge68 said:
Does the car have a FBH? Is there a noise coming from the front LH side?

Hi Nodge, thanks for reply.
Sorry what is the FBH?
A little update on this, is I tried charging my battery, but turns out my charger is cream crackered so just bought a new one.
What I did notice when I reconnected the battery, is the noise has gone (it was drivers side front 99% sure it was alternator). Not heard anything on left. Is the FBH the funny heater thing inside the left front?
As I cant start the FL (flat battery)at the moment I cant see if the issue will return etc. I will update this post in due course but I have some automatic box issues as well!
Thanks to all.

Andy Warren · Nov 19, 2020

6Sabre said:
Hi, I suspect my alternator has a fault.
I can hear a 'hum/buzzing' which appears to be the alternator. (2004 TD4 Automatic)
Has anyone had this or know of the issue. My battery is going flat over a few days, so I suspect it is the issue but at circa £120 I would like to get some confidence it is that.

I have just done brake master cylinder, wheel cylinders, rebuilt the high pressure pump and flushed the auto ( I suspect a dummo garage filled it with the wrong oil giving me the issue in the first place ) I asked for a preventative oil change!!)
The auto still 'thuds' changing gear when cold even with n402 in it, so getting to the point of value re costs etc.
Cheers
Steve

Hi, how long does the buzzing noise last for after the ign. is switch off ? Battery should be charging at 14.2 volts, engine running at 1,000 rpm. I find those 'plug in the ciggie lighter', volt meter/usb devices are quite handy for monitoring charging.

6Sabre · Nov 19, 2020

Andy Warren said:
Hi, how long does the buzzing noise last for after the ign. is switch off ? Battery should be charging at 14.2 volts, engine running at 1,000 rpm. I find those 'plug in the ciggie lighter', volt meter/usb devices are quite handy for monitoring charging.

Thanks Andy, the noise was several days and I think led to the flat battery. Now I have a working charger I will se what happens. Thanks

jedi · Nov 20, 2020

You sure the noise is not the fuel pumps??
And the thud when changing gears could be a solinoid in the auto box

6Sabre · Nov 20, 2020

jedi said:
You sure the noise is not the fuel pumps??
And the thud when changing gears could be a solinoid in the auto box

Thanks Jedi. Not the fuel pump, as this is ignition off/key out noise from the front right of the car. Re the automatic, I am doing ohm checks etc at the moment. Thanks for taking time to reply.

Nodge68 · Nov 20, 2020

The fuel pressure regulator can buzz for a few seconds after the engine is switched off, which is normal. It sounds like a quiet whine, as the valve is pulsed quite fast.

6Sabre · Nov 20, 2020

Nodge68 said:
The fuel pressure regulator can buzz for a few seconds after the engine is switched off, which is normal. It sounds like a quiet whine, as the valve is pulsed quite fast.

Thanks Nodge.

6Sabre · Nov 20, 2020

Ok an update on this- after disconnecting the battery and charging it, on reconnection the noise had gone. However after going for a short run, it has returned when the car is ignition off. Continues all the time. I am getting 14.4 volts so it s charging ok.
Its definitely in the area of the alternator, so will get a new one shortly. Fingers crossed. Thanks for advice guys.

jedi · Nov 20, 2020

Could be somert weird with the alternator I suppose, mine burnt it's coils out, smoke everywhere, but this was with engine running....Could it be the washer motor??? Ac clutch??? Just trying to think what else is down that side that would cause a buzzing noise.

6Sabre · Nov 21, 2020

jedi said:
Could be somert weird with the alternator I suppose, mine burnt it's coils out, smoke everywhere, but this was with engine running....Could it be the washer motor??? Ac clutch??? Just trying to think what else is down that side that would cause a buzzing noise.

Thanks. I have checked and AC clutch appears to be working ok. I have been thinking about this a bit more and nothing else but the alternator would still have power with the ignition off (in that area). I used a hose as stethoscope to listen to parts and pretty sure its the alternator now.

Colthebrummie · Nov 21, 2020

Unplug the alternator whilst it's buzzing, that'll prove it for sure.

Col

andyfreelandy · Nov 21, 2020

You'd need to take the big lead off the terminal to isolate it completely.
Don't touch the car body with it though!!

Probs best to unplug the small wires, then see if it stops, then dis the battery, take the big terminal off and insulate, reconnect battery and then see if it has stopped.

6Sabre · Nov 26, 2020

andyfreelandy said:
You'd need to take the big lead off the terminal to isolate it completely.
Don't touch the car body with it though!!

Probs best to unplug the small wires, then see if it stops, then dis the battery, take the big terminal off and insulate, reconnect battery and then see if it has stopped.

Hi Andy, so I removed the 2 wire plug and it makes no difference. I could have the fun of removing the 'main lead' but that happens when I take battery connector off. I will just live with it for the moment, as long as I use it daily it doesn't go flat. Other more pressing issue on it at the moment! Thanks all for suggestions.

Nodge68 · Nov 26, 2020

Are you 100% it's the alternator? The high pressure regulator isn't far from the alternator, so the buzzing could sound like it's coming from the alternator, when it isn't.

6Sabre · Nov 26, 2020

Nodge68 said:
Are you 100% it's the alternator? The high pressure regulator isn't far from the alternator, so the buzzing could sound like it's coming from the alternator, when it isn't.

Hi again Nodge, would that have power with ignition off? Is that the item on the back of the HP pump? TBH using a tube as a stethoscope Im pretty sure its the alternator. Thanks again for ideas.

Alternator Question

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