Technical Alternator bearings?

[Adam1984]

Hello,

Can anyone with the same engine as me, the 1.2 petrol Otto. (2015)

Tell me of this sounds normal and the same as theirs, or could it be the alternator bearings starting to fail.

Thanks

 

[bugsymike]

Hello,

Can anyone with the same engine as me, the 1.2 petrol Otto. (2015)

Tell me of this sounds normal and the same as theirs, or could it be the alternator bearings starting to fail.

Thanks

If you have a long screwdriver or similar to use as a stethoscope it can pin point the noise quite well .
Just be careful to keep away from moving parts as pulling the screwdriver from your ear can be painful.

 

[Adam1984]

If you have a long screwdriver or similar to use as a stethoscope it can pin point the noise quite well .
Just be careful to keep away from moving parts as pulling the screwdriver from your ear can be painful.

So a mechanic did look at this today and he used the screwdriver technique and said that the bearings are ok.

So who knows what the problem is. He didn't remove the belt though and turn the alternator itself.

 

[Mike1alike]

So who knows what the problem is.

Who says there is a problem?!

 

[Adam1984]

Who says there is a problem?!

I have a really strange noise as the video shows above. And people on other sites are suggesting it was the alternator bearings.

 

[Mike1alike]

I listened but nothing sounded strange to me. To check the alternator bearings just take the belt down and feel the play moving the pulley and feel how the pulley rotates. If there's something wrong with the bearings you sould feel it.
But how old is the alternator? The alternator is an auto part that cannot last forever. What voltage does it put out? If there's something wrong with it, just get a new one and that's it.

 

[Adam1984]

The car is a 2015 reg and as far as I know it has never been replaced.

 

[Mike1alike]

For that age it should be fine at it's core, but could be having problems at the outer end.
If you hear a whistling sound coming from the alternator, it's not the bearings (test them for play anyway, to make sure), but the brushes and worn out contact on the rotor, the slip rings. The outer slip ring usually wears out pretty fast, while the inner one stays almost like new. That happens because it being on the outer side, very much dust gets to it and it gets caught between the ring and the brush. And that wears the slip ring like a grinder and that's the sound you gonna start to hear from it at one point, like the sound made by a grinder.
Here are some pictures in wich you can see the phenomenon.
I got a new alternator after seeing that. Mine was 17 years old at the time and overall was not looking at its best, the bearings were bad and there was a crack in the outer housing, too. So I figured I'd be better with a brand new one.
Anyway, to be able to replace the slip rings you kind of need to take the alternator apart. And if you do that you'd want to put new bearings in as you got to them and overall the cost of rebuilding an alternator is not much cheaper than buying a new one.

 

[Adam1984]

For that age it should be fine at it's core, but could be having problems at the outer end.
If you hear a whistling sound coming from the alternator, it's not the bearings (test them for play anyway, to make sure), but the brushes and worn out contact on the rotor, the slip rings. The outer slip ring usually wears out pretty fast, while the inner one stays almost like new. That happens because it being on the outer side, very much dust gets to it and it gets caught between the ring and the brush. And that wears the slip ring like a grinder and that's the sound you gonna start to hear from it at one point, like the sound made by a grinder.
Here are some pictures in wich you can see the phenomenon.
I got a new alternator after seeing that. Mine was 17 years old at the time and overall was not looking at its best, the bearings were bad and there was a crack in the outer housing, too. So I figured I'd be better with a brand new one.
Anyway, to be able to replace the slip rings you kind of need to take the alternator apart. And if you do that you'd want to put new bearings in as you got to them and overall the cost of rebuilding an alternator is not much cheaper than buying a new one.

Thank you. But I don't have any EML on.

I have MES, would I be able to test the alternator output on here?

 

[Mike1alike]

You wouldn't have any EML because the alternator is not completely dead yet, it still puts out voltage, just not in the optimal way. And that grinding noise is a mechanical thing, I get that that got your attention, the electrical side still functions but it's not ship shape.
You can read the alternator output voltage using MES, but you can also read it by just using a multimeter. The battery voltage is what you need to read while the engine is running.
First thing you can read the battery voltage with the engine off and it being off for at least 2 hours, but it's best if you read it first thing in the morning, before starting the engine. 12.5 V at that reading means the battery is fully charged and the alternator works fine. Less than 12 V means the battery is completely discharged, anything in between it's partially discharged.
Than you start the engine and with it running you read the battery voltage again. Usually, it should be about 14.2 V - 14.4 V or vey similar. Than, engine still running, you turn on electrical consumers and read the voltage again. Turn on all the lights, high beam, radio, heater, rear window heater and so on. The voltage in this case shouldn't drop below 13.8 V. If it's less than that means the alternator is not working at its best.

 

[Mike1alike]

PS: when there are big electrical problems with the alternator, it's not the EML that turns on, but the battery symbol, red lighted.

 

[garyjpaterson]

I have a really strange noise as the video shows above. And people on other sites are suggesting it was the alternator bearings.

My car sounds identical. Is there a problem? Maybe, but I don't think so.

I had my belt off for other reasons last week and whilst it was off I gave the alternator pulley (and A/C) a twirl and they felt fine

 

[Adam1984]

PS: when there are big electrical problems with the alternator, it's not the EML that turns on, but the battery symbol, red lighted.

Perfect.

Thank you. I don't even have a battery light illuminated. But I will test the voltage of the battery through MES over the weekend

 

[Mike1alike]

Alrighty!
Remember to do a voltage reading before starting the engine. That would give you an idea about how good the alternator is. Of course, the battery can be discharged due to short trips or other reasons, consumers on while engine is off an so.
That voltage kind of go like this, in the photo.
And the voltage output when the engine is running will tell you exactly what goes on with the alternator.

 

[euroben]

It sounds completely normal to me.