| Author | Message | ||
     John Rowney Experienced User Username: johnrowney Post Number: 196 Registered: 02-2015 |
Last Sunday driving my Corniche convertible DHC32489 home after a very enjoyable RROCA Qld Christmas luncheon and presentation, I had a FTP about 20 km from my shed. Obviously a bit painful sitting on the side of the road for an hour and a quarter waiting for a tow truck in the blazing westerly sun and the temperature about 38 deg C. A day later, at my shed, the RACQ diagnosed a failed alternator. When I thought back, I noticed that the ammeter didn't move at all during the weekend. Obviously, I had travelled a couple of hundred kilometres without the alternator and the battery finally gave up. I eventually read the SY manual carefully and there were two tests to find whether the alternator or the regulator was the problem. The test for the regulator was simpler - disconnect the "F" contact to the regulator and connect that lead to earth. Being a lazy sort of person, I opted for the simple test first. When the Gen light came on when turning the ignition on, this proved the regulator was the problem. I have ordered a new regulator, so in a couple of weeks I should have the car back on the road. My question is this. Will an alternator fail suddenly, or the sudden failure of the regulator be a real problem? In other cars, the generator or alternator seems to give indications that there is a slower degradation with the Gen light starting to indicate a problem over some time. I would be keen to find others thoughts on this. Cheers John | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 3456 Registered: 06-2009 |
All I can tell you is that I did have an alternator fail suddenly, twice, in a 1989 Cadillac I once owned. The first failure was after decades of use and was the original alternator. Suddenly, the light was on and that was that. The second was with its replacement, which was clearly defective. It worked just fine for a few months, but when it failed, *pop* the light was on again. There was no period of "on again, off again" or dim ALT light with fluctuation in degree of illumination. When that second one was replaced, the car ran again without any issue until I sold it to a friend. Our cars (and yours is of roughly the same vintage as both of mine) can have alternator tests done at pretty much any auto parts store as well, as the alternator is not exotic. By the SY2 era it was definitely an alternator, not a generator. While it is possible to have a regulator failure alone, it's not common. Perplexity.ai: How common is regulator failure in an alternator? | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 2369 Registered: 05-2012 |
I had the opposite scenario - my alternator failed slowly. I noticed the headlamps were dimming too much when the engine was idling. Also the generator light was glowing faintly whereas before it was off. This was in 2016, so I can't remember the tests I carried out. The upshot was, given I am not a purist, I fitted a modern 7127 alternator with built in regulator. It's been great ever since. | ||
| John Rowney Experienced User Username: johnrowney Post Number: 197 Registered: 02-2015 |
Thanks, Brian and Geoff. I didn't have the Gen light come on, and while the problem existed the Gen light only lit up after I connected the lead to the regulator to earth. It will be interesting to see what happens when I put in the new regulator. I have the full records of DRH32489 and there is nothing to suggest that the alternator has been replaced or repaired in the last 47 years. The regulator looks like an original device too. |
