Alternator screeches for 2 months then magically fixes itself.

Joined
Dec 30, 2018
Messages
40
Location
Bosnia and Herzegovina
Weird stuff, I recently (Some might remember me) bought a 1991 Peugeot 309. Since the moment I got it the alternator was showing signs of death, the headlights flicker slightly, battery icon on the dash lights up and flickers sometimes and worst of all the alternator itself was producing the ear-piercing screeching sounds, and continued producing it, until yesterday, now the only noise is the engine working properly. I did absolutely nothing on the car before that happened except fiddle around with the idle speed adjustment, but I highly doubt that would affect it. The alternator belt is fine, brand new, in fact; I don't know much about electrics (hence I only drive old cars) but I know it's either the entire alternator needing replacing or rebuilding or the alternator bearings ( I think that's what they're called in english) being worn. A guy I talked to said it's probably the bearings being worn from non-use since the car's been sitting for the last 2 years and I broke it in. But honestly I wouldn't trust that guy too much, he took an entire bike apart when the only thing he needed to do was replace the spark plug, so I'm not sure how valid that is. Maybe this is somehow really bad and the car is about to explode or something, or maybe a ninja mechanic visited me while I slept and fixed the car for me, at this point anything is possible.
 
Joined
Jan 14, 2015
Messages
2,317
Location
missouri
There are 2 common things that make an alternator screech. 1 Bearings 2 Bad Phase, this can be bad diodes or shorted winding. Bad Phase has a different sound, the pitch varies precisely with the speed of the alternator, while a bearing screech is more variable. If a bad phase then 100 amp alternator now puts out maybe 35 or 50 amps. If the reason was a bad diode taking out a phase they can heal for a while, from the cold and then when it warms up they start again. Bearings rarely heal. It is not uncommon for a bearing to spin in the alternator case and ruin it. Rebuild time. Rod
 
Joined
Dec 15, 2017
Messages
3,275
Location
On another site
Yes sir, that is the correct word to use - bearings (as in bearing the load) I've seen a small stone stuck into an area near a rotating shaft before, making noise until removed. Parbaps this is what happened. I would prepare my budget for a new alternator.
 

Glam_Stachee

Thread starter
Joined
Dec 30, 2018
Messages
40
Location
Bosnia and Herzegovina
Originally Posted by JLTD
Yes sir, that is the correct word to use - bearings (as in bearing the load) I've seen a small stone stuck into an area near a rotating shaft before, making noise until removed. Parbaps this is what happened. I would prepare my budget for a new alternator.
Very possible. And yeah I'm saving up for a new one, problem is I know one guy who knows his way around old electronics and he's currently abroad, I never drove a Peugeot and he had the exact same model years ago, and the alternator doesn't look like anything I've seen on my previous cars, so I don't want to risk putting in any random one.
Originally Posted by Donald
In the USA almost nothing in a car fixes itself. You can turn the radio up but the issue does not go away. New alternator.
Well we all know how French cars are so good they fix themselves, joke joke. And the radio thing was exactly what I did, and I just told people the noise they heard was a turbo charger....most believed me.
 
Joined
Aug 21, 2008
Messages
25,069
Location
ON, Canada eh?
I've heard squeaking brushes that make like a chirping sound but not something like you describe. I would imagine it's a bearing and it's intermittent now but will get worse. The bad bearings that I've heard sound like a file against a metal edge.
 
Last edited:
Joined
Nov 28, 2012
Messages
1,762
Location
Ontario, Canada
Originally Posted by Glam_Stachee
[quote=JLTD] Well we all know how French cars are so good they fix themselves, joke joke.
Watch it Mac ! wink I had a 505 diesel that I loved traded it in at 288,000Km never had a problem.
 
Last edited:
Joined
Jan 19, 2017
Messages
429
Location
Ontario, Canada
I remember there was one episode of Wheeler Dealers they found a replacement bearing which is fraction of the cost of a whole alternator
 
Joined
Mar 21, 2004
Messages
27,997
Location
Near the beach in Delaware
In the USA a alternator re-builder can feel the play and tell you if bearing is good and install bearing or sell it at a decent price. Unsure outside of the USA.
 

Glam_Stachee

Thread starter
Joined
Dec 30, 2018
Messages
40
Location
Bosnia and Herzegovina
Originally Posted by Donald
In the USA a alternator re-builder can feel the play and tell you if bearing is good and install bearing or sell it at a decent price. Unsure outside of the USA.
People who can rebuild them are few and far between here, usually everyone just puts a "brand new" Mk.2 Golf alternator into most cars, I know they work on Yugos, but not if they work on Peugeots, so I'll wait and see
Originally Posted by Pelican
Originally Posted by Glam_Stachee
[quote=JLTD] Well we all know how French cars are so good they fix themselves, joke joke.
Watch it Mac ! wink I had a 505 diesel that I loved traded it in at 288,000Km never had a problem.
Mine's a gasoline, I was never a fan of diesel, even if 90% of cars here are diesel. Literally half an hour ago I passed 90000 km on it, and I intent on keeping the car and properly fixing it up one day, after I do the alternator I only have to get a new blinker relay and from there on out just fix the cosmetics of it (Not looking forward to it, every single side has dents and I gotta hold the plastic door trim on with duct tape.)
 
Joined
Jul 23, 2014
Messages
158
Location
North TEXAS
Maybe the battery was low, and has now finally made it up to full charge, so less load on alternator and belt slipping less. Did you put a new battery, or charge overnight with charger when you first got the car?
 
Joined
Sep 6, 2007
Messages
2,184
Location
TX, USA
The alternator needs to be tested. Otherwise, if it gives up in the middle of driving, the car just stopped. The bad case when the bearing seizes and it breaks the belt to hit anything in the belt path.
 
Joined
Dec 21, 2009
Messages
785
Location
WPB, FL
Eh, alternators are relatively cheap. If the bearings are compromised it can randomly lock up on you and the most inconvenient time.
 
Last edited:
Joined
Dec 24, 2014
Messages
1,215
Location
Huntington WV
Originally Posted by thescreensavers
Eh, alternators are relatively cheap. If the bearings are compromised it can randomly lock up on you and the most inconvenient time.
Yeah you can spend a couple hundred on a new alternator now or a couple hundred each on a tow and new alternator later. When they start squealing they are saying goodbye.
 
Joined
Oct 16, 2010
Messages
2,488
Location
california
I rectified schrreching of my buddies alternator by putting my 40 amp power supply on it for two hours set at 14.7v. It took 40 amps for just over 15 minutes before reaching 14.7v at battery terminals. And was still accepting 5 amps 2 hours later. The battery was obviously very discharged. Voltage after screeching stopped was only 13.2v. And never rose beyond that. After my power supply brought it to mid 14's and held it for two hours then vehicle was able to also hold it above 14 in the driveway. He kept same battery and alternator for 2 more years before selling the truck
 

Glam_Stachee

Thread starter
Joined
Dec 30, 2018
Messages
40
Location
Bosnia and Herzegovina
Originally Posted by oldoak2000
Maybe the battery was low, and has now finally made it up to full charge, so less load on alternator and belt slipping less. Did you put a new battery, or charge overnight with charger when you first got the car?
Nope, haven't got a new battery and neither did I charge it, battery is only 2 years old, both the owner said it and I found the warranty paper confirming it.
Originally Posted by Warstud
Is it warmer outside now compared to 2 months ago ?
Nope, that's what surprised me the most, it screeched when it was much warmer and yesterday it was freezing yet it remained quiet.
Originally Posted by dbias
Originally Posted by thescreensavers
Eh, alternators are relatively cheap. If the bearings are compromised it can randomly lock up on you and the most inconvenient time.
Yeah you can spend a couple hundred on a new alternator now or a couple hundred each on a tow and new alternator later. When they start squealing they are saying goodbye.
Actually alternators here are a couple dozen bucks only, but I don't have anyone available who I would trust finding a good one right now, lots of shoddy mechanics where I live. And I'm not too worried on getting stranded, for one I don't drive too much or too far for the time being and I got a tractor to tow the car if need be.
 
Joined
Mar 16, 2018
Messages
552
Location
Green Bay, Wisconsin
Originally Posted by Glam_Stachee
A guy I talked to said it's probably the bearings being worn from non-use since the car's been sitting for the last 2 years and I broke it in.
For now, I'm with that guy. I've started cars that sat for years, and some accessories made some rather awful noises, for a while. And then were fine. I wouldn't think the bearings are worn. More that maybe they had corrosion on them from sitting that had to be burned off or was interfering with lubrication or something. Consider how awful a power steering pump can screech at you when low on fluid. Then you add fluid, and a bit later it sounds fine and works fine. Did running it low on fluid shorten its lifespan? Probably. To such a noticeable degree that it soon requires replacement? Probably not. Can I predict the future and say you shouldn't replace the alternator now? The future is currently hazy. Cannot predict now. Ask again later.
 

Glam_Stachee

Thread starter
Joined
Dec 30, 2018
Messages
40
Location
Bosnia and Herzegovina
Originally Posted by DejaVue
Originally Posted by Glam_Stachee
A guy I talked to said it's probably the bearings being worn from non-use since the car's been sitting for the last 2 years and I broke it in.
For now, I'm with that guy. I've started cars that sat for years, and some accessories made some rather awful noises, for a while. And then were fine. I wouldn't think the bearings are worn. More that maybe they had corrosion on them from sitting that had to be burned off or was interfering with lubrication or something. Consider how awful a power steering pump can screech at you when low on fluid. Then you add fluid, and a bit later it sounds fine and works fine. Did running it low on fluid shorten its lifespan? Probably. To such a noticeable degree that it soon requires replacement? Probably not. Can I predict the future and say you shouldn't replace the alternator now? The future is currently hazy. Cannot predict now. Ask again later.
Can't speak about power steering pumps, since I've never owned a car that had one (Actually my first car did have one but it was already kapput when I bought the car). And yeah I'm a lazy [censored] and I'll probably just gonna hold off replacing it until it dies. After wasting 5 hours replacing my side mirror on the thing and having to cut into the door frame because one screw had broken thread I'm sick of working on anything for a while.
 
Joined
Jan 13, 2013
Messages
4,161
Location
Texas
I have used one of these before . Could tell if it was the front bearing or the rear bearing that was noisy . https://www.harborfreight.com/catalogsearch/result/index/?dir=asc&order=EAScore%2Cf%2CEAFeatured+Weight%2Cf%2CSale+Rank%2Cf&q=stethiscope Do not know if they are available where you live , but I would think so . Be careful around moving parts . Alternators can often be rebuilt as long as the winding are not bad . But honestly , I just replace them . Best of luck to you , :-)
 
Top