Alternators

[Billy Smalls]

Hi

I have a hunch that my alternator is on the way out. The heater fan struggles unless the engine is high revving (full choke or booting it) and there is now a whistling / whining noise and it's either the alternator or the Borg Warner.....that'll be fun if it is!!!

What a good way of checking? I have a multi-meter but don't really understand how it works????

It's the Bosch K1 on a 1970 144

Thanks

[Billy Smalls]

I've had the Borg Warner looked at - it's not that, thank God.

Any ideas on the alternator???

anyone??

[classicswede]

What does your multi meter say the alternator is doing?

[Billy Smalls]

Originally Posted by classicswede

What does your multi meter say the alternator is doing?

Very grateful for you getting back to me.

That's the problem, I have no idea how the meter it works. Am I reading volts, amps or ohms?

I worked out how to measure volts from the battery with it just cos even I know polarity and that it should be 14 volts and it is indeed 14.5v

What should i set the meter to, what do i put the probes on and what should it say

Lots of dickless questions, i know. Thanks a million

[guitarman]

The meter typically should have a revolving dial with different options for amps, resistance and voltage. Is it digital? If not I suggest buying a basic digital model new, only about £20.
I had an alternator pack up on a Fiat not long ago. At first I thought it was the voltage regulator but alternator it was.
The Haynes manual shows you the basics of the alternator and charging system; as you said you should get 14.5 volts.
Electrics aren't my strong point; however I've found 90% of faults are due to bad earthing, poorly soldered joints, corrosion . Being able to test continuity and measuring resistance are very useful and simple ways to pinpoint problems without resorting to pulling things apart. Sorry I can't be of more assistance; I'm lucky to have help on cars; at least for now!

[guitarman]

...and beware of the high tension part of your car's electrical system!

[Billy Smalls]

Thanks guys; I will see if youtube has a dummy's guide

This whining / singing / squealing noise is definitely under the bonnet; I've tried a wooden spoon to my ear but can't tell where it's coming from.

The combination of the noise, plus lack of power to the heater fan is directing me to the alternator but maybe not????

cheers

[classicswede]

https://www.youtube.com/watch?v=LGB6ZEjGm7Q

[Billy Smalls]

fantastic - thanks Mr. Swede!!

[Billy Smalls]

Hi, I studied the tutorial on youtube and tested mine, with the following results.

Using a decent enough digital multi meter; with enigine at running temperature

Engine off and no electrics on = 13.25V
Engine on and no electrics on = 14.25V
Still engine running, with full beam, hazards, radio and wipers on full = 12.85V
Engine switched off and electric items all off = 12.90V

I then did the 'voltage drop test' as described in the video and there was no problem there.

But with those readings, am I looking at a weak or dying alternator.

Thanks alot for any help