Alternator troubles

[tejb1]

Hi guys, hoping you can again shed some light on something that happened today! I think the problem is sorted, but would appreciate input from those who know way more than me...

Did a good 250 mile round trip today going to have lunch with a friend who lives in Norfolk from London. On my return, I stopped at a petrol station to fill up, accidentally leaving the headlights on. When I started the car again there was a loud rattling sound as it started and the alternator light came on dimly. I assumed that this was connected to my leaving the lights on and drove off. Down the road, wipers on, slow as hell and light goes bright red. Uh oh. Carried on a bit further, light comes on when braking or using indicators (which are flashing faster than normal). Pulled over, stopped, engine still running, light out, nothing obviously wrong under the bonnet, so carried on. A couple of miles down the road, same thing. Wipers back on, slowing down, eventually they stop mid-sweep and the ignition dies.

Pulled over at the side of the road (pouring rain, too, thankfully I keep a waterproof in the back) and got the bonnet open. Checked the fanbelt, seemed sufficiently tight, then checked the alternator connections, the rear one seemed a bit loose so re-seated it, inspected the fuses (all seemed fine). Got back in and it fired up perfectly first time, alternator light out, seemingly fine. Plugged in a cigarette lighter voltmeter I keep in the boot which was recording a good 13.2v (with wipers and lights).

Whilst thanking my lucky stars that I'd got it going in about 2 minutes again, I was worried that it might recur, but the remainder of the trip went fine. I was assuming that the increased load through trying to turn the starter motor AND power the headlights, caused a severe vibration (hence noise) which dislodged the connector, thus causing the alternator to stop supplying power? If so, the only thing that doesn't fit is that the car ignition died (which I assumed was through it running off battery and then the battery dying) but the battery was capable of starting again without a struggle. And is it normal for such a vibration to occur when starting under load, or is this a sign of the alternator being on its way out?

cheers guys, any insight or even being told not to worry, is appreciated!

[Paul G]

It's a strange one, the joys of old cars. I would certainly clean up again all the alternator terminals as well as cleaning and checking the engine earths and also clean up the connections on the starter motor.

Finally, are the battery terminals clean and tight?

[stevemarl]

I would certainly clean up again all the alternator terminals as well as cleaning and checking the engine earths and also clean up the connections on the starter motor.

Finally, are the battery terminals clean and tight?

Don`t forget the braided leads between engine and body.

[caprikid61]

I had much the same problem last year , it turned out to be water getting in to the fuse box . I put a plasic bag round the fuse holder and cleaned/dried all the fuses never had the problem again. Mind you it was heavy rain when it happend but worth a try anyway.

[tejb1]

Apologies, I forgot to reply to this. Thanks to all for your suggestions. I've done a check and clean up of the battery terminals (1 slightly loose), earthing points, fusebox (generously applied contact cleaner and checked connexions) and alternator cables, done a good 150 miles since it happened and no issues!