alt not squealing anymore...

[timandbim]

so my alternator belt had been slipping a lot over the last month esp in very cold weather. i tightened it as hard as i could (a couple of times) and it didn't seem to be helping.... belt looks brand new (bought car in july '07) and alternator was charging fine except of course when the belt was slipping. anyway... i sent some wd40 down by the drive wheel on the alternator and let it rev for a bit and i haven't heard from it in three days now. cool! (i hope...) not sure if this would be ridiculously obvious to all of you but i didn't see anything in old threads so i thought i'd post it for people like me, even if it only delays the inevitable. (i'll post if it dies) anyone think i should use (ahem) better lube (ahem) down there? (go easy, lads)

[Morgenster]

I'd keep a serious eye on that because I'm not sure if using wd40 on the drive wheel is a good idea in the long run. Maybe someone else can give better advice; but as far as I understand a very thin waterdisplacing lubricant like wd40 can loosen stuff that went a little rigid but if the bearings inside relied on grease the wd40 might have watered the grease down.

But then again, I hope your fix actually did the trick and got rid of the squeal for good.

[timandbim]

yes i think i will regrease with white lithium later on when working on the car isn't such a nightmare. so far it's working great though, it seems to have fixed a minor idle stutter too - i think it even made the car stall once before, now it's smoother than it's ever been.

[whiskychaser]

I'd keep a serious eye on that because I'm not sure if using wd40 on the drive wheel is a good idea in the long run.
But then again, I hope your fix actually did the trick and got rid of the squeal for good.
x1
I hope you didnt get any on the belt - it would still slip but you wouldnt hear it cos of the lube :) Would have a look at the alternator front bearing some time soon

[Ross]

x1
I hope you didnt get any on the belt - it would still slip but you wouldnt hear it cos of the lube :) Would have a look at the alternator front bearing some time soon
Yes the lube will quiet a slipping belt but not prevent it from slipping.
I suspect your noise will turn out to be the alternator bearing. If you have well tightened the belt and noise persists start thinking about bearings.
Remove the belt and turn whatever that belt goes around, whatever is grinding is the culprit.
An overtightened belt will certainly cause or worsen these problems.

[timandbim]

Yes the lube will quiet a slipping belt but not prevent it from slipping.
I suspect your noise will turn out to be the alternator bearing.

yes i think it's the bearing too, gosh my list for spring is long. i've hardly been driving but so far it's pretty amazing what a difference this has made not just to the charging system but i even have more engine power all round and the idle is like it's a new car! errr, guys i didn't lube the belt, i was aiming for where i supposed the bearing to be... and i was careful i didn't just spray it all over the place.... i'm a noob but i'm a careful noob. i guess my question was what kind of grease should i use to regrease the grease on the bearing? is that white lithium stuff good for this?

[Rus]

The bearings in the alternator are likely sealed, so getting any sort of lubricant into them would be quite difficult. White lithium grease would certainly be too thick to make it past the bearing seals/shields. You may be able to replace the bearings though if you can locate a source for them (alternator rebuild shops?) and pull the old ones out/press new ones in. Just my $.02

[whiskychaser]

yes i think it's the bearing too, gosh my list for spring is long. i've hardly been driving but so far it's pretty amazing what a difference this has made not just to the charging system but i even have more engine power all round and the idle is like it's a new car! errr, guys i didn't lube the belt, i was aiming for where i supposed the bearing to be... and i was careful i didn't just spray it all over the place.... i'm a noob but i'm a careful noob. i guess my question was what kind of grease should i use to regrease the grease on the bearing? is that white lithium stuff good for this?
Didnt intend to insult your intelligence:) As Rus said, you wont get grease into that bearing. Best bet is see if there IS any wear on it and go from there. I should add that I had a rather worrying squeal and metallic tap on mine. Didnt believe for a second it would go when I replaced the belt but it did! A wiser man said belts can make all sorts of funny noises if they get antifreeze on them. Worth a look?

[timandbim]

The bearings in the alternator are likely sealed, so getting any sort of lubricant into them would be quite difficult. White lithium grease would certainly be too thick to make it past the bearing seals/shields. You may be able to replace the bearings though if you can locate a source for them (alternator rebuild shops?) and pull the old ones out/press new ones in. Just my $.02
thanks Rus - no offense taken wc and i appreciate the advice - i don't think i gave a good description of what i'd actually done... i hardly used any oil and i used a little red guide tube hoping to let it seep into the seals on the drive wheel of the alternator - i can't believe how well my car runs and charges since i did this it's totally unbelievable. i'm going to check everything down there in the spring, see how it goes and maybe try to change the bearings then but for now i'm pretty happy just to spray and pray...

[Rus]

If you do spray something down into the bearing area, try to use something other than WD-40. WD means Water Displacer, which doesn't have much in terms of lubricating oils in it. Other oils are available in spray cans and may be more beneficial for your purposes. HTH

[chinist]

A new belt that still slips can mean a worn out pulley. If the belt is bottoming out in the pulley it's not contacting the sides hard enough to drive as designed. Check to see if top of belt is above the pulley groove a fair amount ...

[robert g]

I had the same thing and what I did was take the belts off and spun the pulleys and the alternator. The alt made a grinding sound it wasnt that. Spin it and sounds like a bearing from a skateboard. It is one of the three idle bearings. I did some write up on this a few months back. Check it out.. Might help.. Let me know if you have any look... I did the same thing sprayed the whole car with wd40. I replaced the bearings in the alt. for a few bucks replaced the voltage regulator brushes because I couldnt fing the whole regulator for my car. Valeo alt.... I ended up replacing two of the pulleys bearings. It is like if it was new car.. It sounded like I had a bird under the hood of my car... Not good when you pull up in bmw and sounds like it shouldnt... Let me know

[timandbim]

So the problem is slowly coming back. The belt is not slipping at all but i can feel the engine struggling like before a tiny bit in really cold weather at idle and the 'terminal r' obc test shows a corresponding drop in voltage as the rpms go down a tiny bit. It's not that bad a problem right now at it's worst I still get 12.9v or more charge and normally it's 13.5 or more... for sure i'll replace the belt and check the bearings but for now i'm hoping to make it to spring when i can park the car for long periods and ride my bike to work.

This morning i put a dab of marine grease on the wheel (arrow) and tried to kind of wash it into the assembly with a quick burst of you-know-what - it helped a bit I think. I used very little of both (more grease)- you guys think this is a bad idea? There is zero belt slip or squeal, I think it could be on tighter but it's pretty tight. If the belt is grabbing always and there is resistance in the alternator wheel/bearing it does make sense that this would have an effect on the engine idle doesn't it? Thanks guys...

pic of my lube arsenal - only used the grease and little blue can so far in this case.