Dead alternator?

[Softshoe]

Hi all

Just come back from a short run in the Stag, the last couple of miles of which was stuck in the roadworks approaching Bedford on the A421 so I was keeping an eye on the temperature gauge.I noticed that the volts gauge was only reading 11, normally this reads fractionally over 13. When I got home I switched the engine off while I opened the garage door andmoved some stuff: when I tried to start the engine again it struggled to turn over but did eventually start. I did a quick voltage check on the battery - 12.3 volts.

Does this indicate a dead alternator?

Thanks & regards

Andy

[Giles]

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I am no auto electrician but if you put a voltmeter accross the battery you should see the volts go up when you start the engineto 13.5 ish i think - otherwise I would have thought the alternator is not looking good

[StagnJag]

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Do you have an electric fan fitted? If it kicked in in the traffic you would see the voltage drop as they take a high current draw.

Regards

Dave

[V Mad]

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Best check for an alternator is a follows:

Measure the battery volts (engine off): This is normally about 12 t0 12.5 volts.

Then start the engine, run at fast idle >1000 rpm, then measure the volts (should be about 13 volts). Then switch on all headlamps full beam, and measure volts again. They should only drop a little. If they drop to 12 volts the alternator is not charging.

If the alternator is not charging you should also get the red IGN light coming on (unless wire has come off or lamp is blown)

[Softshoe]

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Thanks to all for your advice.

Checking the voltage with the engine running and off produced almost exactly the sameresult and on attempting to restart it the engine only just turned over. Speaking to Mick Ward this morning he mentioned that there seemed to have been a bad batch of renovated alternators as they'd had a few problems. He also suggested that fitting a brand new uprated alternator might be the way to go as I've got an electric fan fitted and slow moving traffic near homeis the rule. This is likely to continue until late 2010 when the new road from Junction 13 of the M1 to Bedford is completed.

My membership renewal is due shortly and I had been doubtful about renewing it as the magazine has become of virtually no interest and its arrival is still unpredictable despite the quoted aim being for delivery by the 7th of the month. However, I would miss this forum, even if I'm not a particularly active member, and the swift and helpful advice I've had makes the subscription worth every penny.

Regards

Andy

[V Mad]

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Softshoe wrote:

Thanks to all for your advice.

Checking the voltage with the engine running and off produced almost exactly the sameresult and on attempting to restart it the engine only just turned over.

Alternator is definitely not charging, but is your IGN lamp staying on?


.....................He also suggested that fitting a brand new uprated alternator might be the way to go as I've got an electric fan fitted .................

If you fit an uprated alternator your wiring might need uprating too; I think the 18ACR is fine even with an electric fan.

[V Mad]

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Softshoe wrote:

Thanks to all for your advice.


My membership renewal is due shortly and I had been doubtful about renewing it as the magazine has become of virtually no interest and its arrival is still unpredictable despite the quoted aim being for delivery by the 7th of the month.

However, I would miss this forum, even if I'm not a particularly active member, and the swift and helpful advice I've had makes the subscription worth every penny.

Regards

Andy

Graham, the forum (unlike the mag) is clearly saving the club from membership attrition!