alternator issues AGAIN

GS608 · 12-06-2011, 12:36 PM

Having no luck with this. I have a feeling the alternator might be stuffed or on its last legs but just wanted to make sure it's not something simple like the belt slipping.

It's an intermittent issue, the alternator light comes and goes as it pleases, when it's on most the time the voltage stays constant, sometimes though it will drop down to 10 on the gauge, after idling for a bit there is a very distinct noise that starts up (like a whine) and the gauge will rise back to normal. I've noticed with the sub in the car it drops a lot more often and when driving at night with the headlights on it will drop almost instantly and won't return until i park it and idle with everything off. Could this be wiring as i replaced the original alt with one from a wrecker that we bench tested to be fine about 6 months ago.

Last month i noticed the power steering leaking onto it so replaced the o ring and degreased/cleaned out the alternator and it started working fine for a few days.

FWIW the replacement was a motorcraft, don't really have a spare $250 sitting around to get the wiring kit and a new mitsubishi alt.

ronwest · 12-06-2011, 01:10 PM

Quote:

Originally Posted by 5.0

Last month i noticed the power steering leaking onto it so replaced the o ring and degreased/cleaned out the alternator and it started working fine for a few days.

I'd probably give this another go. I had similar symptoms and degreased then washed out, then blew out with compressed air a couple of years ago and it's still running fine.

My brother had the same prob, did the same as me and it played up again in a couple of weeks. He gave it another drubbing and it's been working fine for over 12 months now.

If that fails, and money is a bit tight, it's not particularly difficult to replace brushes (may be low and sticking a bit). It's a few years since I've pulled an alternator apart but I think the brushes were <$20.
It may be the voltage reg (pull alternator apart job) - I'm not sure of the cost but can't imagine it's be any more than $50 (diy). You can get brushes or reg from your local auto electrician.

If all of that is a bit much, give it a degrease, wash, try it, and if no go look at the wreckers for another second handy, or a recond unit from auto elects (I think around $150 - someone can give a more accurate figure?)

edit: oh, it shouldn't be a slipping belt. There'd be other things slipping before your alt. Just to make sure, slip the belt off and spin the alt by hand. If it spins freely and doesn't make ugly noises it's not likely seizing. You can also look at the inside of the belt. It won't be hard to see if there's an issue.

GS608 · 12-06-2011, 02:55 PM

Thanks for the advice mate, will pull it off and give it another clean see how we go. With the brushes etc I was told that the motorcraft alternator is a real ***** to recondition?, which is why nobody stocks em, if you want new or reco you have to get the mitsubishi one.

4ford · 12-06-2011, 03:08 PM

Just for info, that "a very distinct noise that starts up (like a whine)" is the normal noise for my alternator, has been ever since I can recall.

Had the local auto elec guy check it out, he says that noise is quite normal!

Cheers...

mik · 12-06-2011, 06:03 PM

just as a matter of interest how many k`s does your alternator have on it 5.0? i`m a bit surprised mine is still going at 192000 `ks, pretty happy with the service life myself.

GS608 · 12-06-2011, 06:17 PM

cheers for that 4ford. good to know its normal.

mik, what i assume was the original alternator (only owned it since 180xxxkm) lasted till about 210,000 or so this one i have no idea what kms are on it as it's from a wrecker.

Road Games · 12-06-2011, 06:23 PM

Come around tomorrow mate and we can go through it together

mik · 12-06-2011, 06:34 PM

cheers mate, good luck with it.

GS608 · 12-06-2011, 06:34 PM

Cheers daz, sent ya a pm.

Just got back from a quick drive, during it the voltage dropped right off and for about 5-10 minutes all electrics stopped working, cluster etc..got on the M1 about a minute or two later everything came back on voltage back to norm, the whole drive home (20 minutes or so) it stayed constant no battery light either. Have a feeling it won't last long though lol.

david lee · 14-06-2011, 07:41 PM

Quote:

Originally Posted by 5.0

Cheers daz, sent ya a pm.

Just got back from a quick drive, during it the voltage dropped right off and for about 5-10 minutes all electrics stopped working, cluster etc..got on the M1 about a minute or two later everything came back on voltage back to norm, the whole drive home (20 minutes or so) it stayed constant no battery light either. Have a feeling it won't last long though lol.

good luck but i wouldnt trust it i had the same priblem and replaced it

**aussiblue** · 12-06-2011, 07:40 PM

Quote:

probably give this another go. I had similar symptoms and degreased then washed out, then blew out with compressed air a couple of years ago and it's still running fine

I'm surprised as degreaser will using wash the grease out of the alternator bearings so they get noisy then seize.

ronwest · 13-06-2011, 12:38 AM

Quote:

Originally Posted by aussiblue

I'm surprised as degreaser will using wash the grease out of the alternator bearings so they get noisy then seize.

As I said earlier it's a while since I've pulled an alt apart but from memory the front bearing is sealed and the rear is actually a bush (at least on the alts I've played with).

In any event, it's something over 2 years and probably 30+Ks so it's doing ok

Road Games · 12-06-2011, 07:45 PM

Mate i have emptied endless cans of carby cleaner in and around the alt while painting things in my BA and so far no probs

AMB · 13-06-2011, 11:04 AM

Quote:

Originally Posted by 5.0

... after idling for a bit there is a very distinct noise that starts up (like a whine) and the gauge will rise back to normal.....

yeh like 4ford said, that noise sounds like it is alt loading up when it is charging, then the intermittent fault occurs and the alt unloads again (spinning freely with no load). I would check for bad connections everywhere, including a bad earth to the alt (run a earth wire from bat neg to alt case to check). The next thing would be to check the contacts on back of the regulator (each screw holding the regulator on has a contact point on the back of the reg, they get all corroded and make bad contact). Otherwise your reg is stuffed.

Road Games · 13-06-2011, 01:06 PM

While you gurus are in the house ? I have fluctuating lights at the moment , quite annoying at night and really noticeable with interior light's on ...

Measures 14.1 at the battery with everything turned on at idle and drops to 13.96 @5000rpm .. 20% underdrive fitted.. It has only just started doing this, i made sure all the earths in the engine bay are tight, maybe i have dirtied up the contacts with my cleaning/painting ??

GS608 · 14-06-2011, 02:26 PM

Thanks for the help fellas, nothing worked, guess its dead. Borrowed some cash and went grabbed a Mitsubishi alt from a wrecker..along with the rework kit. Works great, took probably hr and a half or so. Rewire was easy as, just cut off the old connector and crimp/solder on the new spade bits, into the connector all done.

Road Games · 14-06-2011, 07:47 PM

Great to catch up Dean .. hopefully tomorrow arvo we can catch up again