Telstar AR 1985 - Alternator Noise

[Flokos]

Dear all,
(Ford Telstar Ghia Feb 1985 AR, 2Lt, 4Cyl)
High-pitch noise appears to come from the alternator, occasionally when driving at low speed, and sometimes at high speed, causing Voltmeter indicator moving to 16 Volts, and the RPM meter moving upwards very erratically.
Am I cooking the cables and instruments with this erratic high voltage (or current) problem?
Even when warming up at Parking mode and disappears when moving gearstick to Drive (then, the usual problems above).
This forces me to drive down to 10-20k and the problem is fixed sometimes.

Inspected alternator brushes (no roughness on contact sufaces) but should I suspect voltage regulator? Maybe faulty distributor control box?
The alternator belt is quite tight and new, and links with the pulley very straight (not at an angle). But the noise is from the alternator and the high noise really scares me - looks like it may explode (another episode of Dr.Who)? Any help would be appreciated. Flokos.

[Russ]

When you say the alternator belt is tight, how tight ? If it's too tight it may well be causing strain on the internal bearings. I would first try loosening the belt slightly and then trying again. If this make no difference and you're sure the noise is definitely coming from the alternator then I would suggest having it checked or picking up an exchange unit. As far as the voltage changes are concerned how accurate are the instruments ?

[Flokos]

Many thanks Russ, I will check on the tightening of the belt. Voltage reading is from the instrumentation panel. The alternator is the original one (Feb 1985) and the car has done 245,000 kms. I suppose it's time to find a reconditioned one? Flokos

[Flokos]

Hi Russ, the noise has been eliminated by the tightening of the alternator belt. However, during my recent trips, I've noticed occasionally the oversupply of voltage (perhaps current too) to the instrumentation panel, causing the voltage reading to exceed (I think) the 16 volts, and the revolutions meter moving erratically. To avoid this ''oversupply'' I have to switch on the fan speed to the maximum 4, and to switch on the head lights to the 1st level (not the normal level of full lights for night driving).
This action eliminates the erratic readings of the revolutions meter, but just, as I have to also slow down about 45-50kms. Still, the voltage meter shows the 16 volts plus reading....
This car seems to have a mind of its own...
I suspect faulty diodes on the alternator (ie. perhaps a new alternator is now unavoidable?), but I'm not certain yet... Comments would be appreciated with many thanks, Flokos

[Russ]

Hi Flokos,

I would recommend having an auto electrician check it out for you, you may have a faulty voltage regulator in the alternator and if your instruments are correct and it is producing 16v that can, and most likely will, cause damage to other electronics if allowed to continue.

Cheers

[Chief Tool]

16v is definitely no good, I boiled my battery when the regulator failed and its was doing about 16.5 volts.

[Flokos]

Gentlemen, many thanks. Alternator was definitely the problem, now replaced and all fixed :-) Flokos.

[Russ]

Cheers mate, pleased to hear it's all sorted