cliffpeters Posted May 26, 2007 Report Share Posted May 26, 2007 Recently, my 6 has started running in the C range of the ammeter. Weirdly, it has only been occasionally doing this. The needle would be just a bit into the C range. Other times, it would appear to be fine, the need pointing straight down on the C/D border. But yesterday, I noticed it was almost pegged in C, especially under revs. When I would be closer to idle, the needle came back down, but was still in the C range. This morning, I went out and started it up and it was still running well into the C range. Does this look like new alternator time? Any thoughts from the more mechanically/electrically astute? Maybe the meter? The leads to the battery are good and the battery itself is less than a year old. Would appreciate your advice. Thanks, Cliff Quote Link to post Share on other sites
john.r.davies Posted May 26, 2007 Report Share Posted May 26, 2007 Cliff, No doubt those with more electrical knowledge will help, but "C" should mean 'charge' and "D", 'discharge'. My interpretation is that the alternator is fine, it's the battery that has a problem, as there is an excess of current going out of the alternator in these circumstances. Or an excess of smoke in the wires. Good luck. John Quote Link to post Share on other sites
cliffpeters Posted May 26, 2007 Author Report Share Posted May 26, 2007 Cliff,No doubt those with more electrical knowledge will help, but "C" should mean 'charge' and "D", 'discharge'. My interpretation is that the alternator is fine, it's the battery that has a problem, as there is an excess of current going out of the alternator in these circumstances. Or an excess of smoke in the wires. Good luck. John Thanks John. I've since put a multimeter on the battery and it seems OK. It gives 12V, which momentarily drops to 11V on startup and shows a steady 13V at idle. That would seem to me to be in the nominal range for the car, but I'm no expert. It is a very new battery (but that doesn't mean it isn't duff), but the car starts right up with good cranking power. I wonder if it's the gauge. With the car running (and the gauge reading in the C range) I turned on the various power accessories, like headlamps, heater fan, etc. and with all that stuff running, it dipped into the D range a slight bit at idle. So I'm wondering if something suddenly has affected the amplitude of the meter. So far, despite this change, the car still seems to run fine. Only the owner's blood pressure is rising! Cliiff Quote Link to post Share on other sites
stuart Posted May 26, 2007 Report Share Posted May 26, 2007 Cliff if you are running an original alternator with the seperate control box it may be that it is giving notice. Or if you have a later type without it may be the diode pack on its way out. Provided it isnt charging too much and starting to boil the battery I would just keep an eye on it and as they say "let it develop"! You dont say what voltage it produces at higher RPM, it shouldnt exceed 15 volts. Stuart. Quote Link to post Share on other sites
cliffpeters Posted May 26, 2007 Author Report Share Posted May 26, 2007 Cliff if you are running an original alternator with the seperate control box it may be that it is giving notice. Or if you have a later type without it may be the diode pack on its way out. Provided it isnt charging too much and starting to boil the battery I would just keep an eye on it and as they say "let it develop"!You dont say what voltage it produces at higher RPM, it shouldnt exceed 15 volts. Stuart. It seems to be pretty constant 13V, according to my friend who was watching the meter. I revved it to 3000rpm. Thanks, Cliff Quote Link to post Share on other sites
jonlar Posted May 26, 2007 Report Share Posted May 26, 2007 Hi Cliff, 13.8 Volts is the recognised sort of figure that is to be expected. As Stuart says, if it's getting up above 15, definitely too high. You can buy Regulator/Diode assemblies for the built-in type ACR alternators, easy enough to replace, clean contacts up and replace brushes. Quote Link to post Share on other sites
cliffpeters Posted May 27, 2007 Author Report Share Posted May 27, 2007 Hi Cliff, 13.8 Volts is the recognised sort of figure that is to be expected. As Stuart says, if it's getting up above 15, definitely too high. You can buy Regulator/Diode assemblies for the built-in type ACR alternators, easy enough to replace, clean contacts up and replace brushes. Thanks. I'll check that out. While it rained yesterday, I also changed the oil and filter. When I was finished and started up the car to check for leaks, I noticed that the alternator was occasionally making a little chirping noise that I don't remember noticing before. Or am I just hearing things too??? Cliff Quote Link to post Share on other sites
jonlar Posted May 27, 2007 Report Share Posted May 27, 2007 Hi Cliff, chirping as in bearing noise or shriek as in fan belt slipping - needs tightening a bit? Quote Link to post Share on other sites
john.r.davies Posted May 27, 2007 Report Share Posted May 27, 2007 Hi Cliff, chirping as in bearing noise or shriek as in fan belt slipping - needs tightening a bit? WD40 on the belt will stop the second , but not the first. John Quote Link to post Share on other sites
jean Posted May 27, 2007 Report Share Posted May 27, 2007 In most cases it's the blades of the alternator cooling fan touching the body. The disk is squeezed between washers and tightening the belt a little further can make the difference. With a screwdriver you can push it away from the alternator body. Quote Link to post Share on other sites
cliffpeters Posted May 28, 2007 Author Report Share Posted May 28, 2007 In most cases it's the blades of the alternator cooling fan touching the body. The disk is squeezed between washers and tightening the belt a little further can make the difference. With a screwdriver you can push it away from the alternator body. It sounded like a bearing to me but it could be the blades. It was every so often, not constant. The guys at yesterday's Thames Valley Group meeting in the dripping wet of another UK Bank Holiday seemed to agree that my problem is the rectifier in the alternator. I'm going to try to perform the alternator test in the manual or have it looked at by an electrical guy just to be safe. I've got a trip planned in a couple of weeks and don't want to be worrying about it. Thanks for all the help. Cliff Quote Link to post Share on other sites
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