Alternator Bearing Clatter: When would you replace?

[lobo411]

Hi all,
My alternator bearing is starting to go (OE, 160k mi, 1996 4.0 OHV), and I'm wondering how long you all might wait before you decided it was time to replace it. Right now, the sound is just a clatter--maybe 5-10 seconds of quiet followed by a 2 second "clack clack...clack clack clack clack" sound, repeated as long as the engine is running. It's quiet enough that only I can hear the problem right now.

I put a mechanic's stethoscope over the bearing and I can hear it clearly there when the engine is running. I pulled the belt and rotated the pulley by hand, and it sounds "gritty." I then rotated the water pump just to be sure, and it's nice and quiet, so I'm sure it's the alternator bearing.

So I'm wondering at what point people would consider it prudent to replace the alternator. Immediately, so you don't take a chance on getting stuck? Wait until the noise is more obvious? Wait until the pulley falls off?

My thinking is that I should either:

A. Replace immediately, since I drive 300 miles r/t for work one day a week and I would hate to get stuck out in the middle of nowhere, or

B. It's going but not gone. Wait, especially since I have smog coming up in 3 months and who knows if the car will pass.

Also, I have a standard Explorer 4dr XLT with nothing too fancy on it. I assume I have a standard 95 amp alternator too, right?

Thanks!

 

[koda2000]

considering how many miles you're driving, i wouldn't wait. you're going to have replace it eventually and it will only be a more expensive job if you wait until the bearing seizes. it's an easy job to do. i got one from AZ recently. took about 15 mins to change and cost around $120 (with discount code) 130 amp w/lifetime guaranty.

are you positive it's not the water pump making noise?

 

[toypaseo]

IMO, replace it ASAP.

It sucks when an alternator freezes, belt breaks, and leaves you stranded. Then it is more of a PITA to get a ride somewhere, get replacement, get tools, get back to vehicle, and install it.

 

[bill06447]

I'll take "A" for 300

Bill

 

[SoNic67]

Consider being stranded at 150 miles from home. What's the game plan? Towing?

I would replace immediately. Use a code from retailmenot for online ordering at Advance Auto Parts - with local pick up.
Get the "new" one (130A). Or the Bosch reman if you feel generous.
Change it at home in 10-20 minutes.

 

[delexploder]

Just a thought, if money is tight or you are just a cheap ****** like me, its not hard to rebuild one, I keep a couple of milk crates full of starters, alternators, and I just take them apart and swap good parts around or buy pieces,

 

[rb142]

I would replace it immediately. No benefit to waiting. And avoid the cheap reman parts, which end up costing more after frequent replacement.

 

[koda2000]

one thought on rebuilding... these alternators tend to have a bad shaft as well as the bearing. still if you want to go ultra cheap, get one from the salvage yard and keep your fingers crossed.

 

[lobo411]

Thanks for the feedback, guys! Frankly, I wasn't even thinking about the possibility that the shaft could seize (I was thinking more along the lines of it getting progressively loose), so I'm going to replace the alternator immediately.

Went with the Duralast Gold 95 Amp (new) for $144 w/ taxes. Pep-Boys has an equivalent for $10 cheaper, but Autozone has 4000+ stores and Pep-Boys has like 400, so I figured I'm safer w/ Autozone in case anything happens and I need a warranty replacement. Advance Auto hasn't gotten to SoCal yet. Rockauto and Amazon have it about 30% cheaper (around $100), but then the problem is what do you do if you need warranty service?

The backup plan was/is AAA Plus, which gives me 1 200 mile tow free per year. But it would still suck to get stuck anywhere, especially if it conked out on the freeway during rush hour (I leave at 5 AM and don't get home till 6 PM).

Thanks all!

 

[my98nnj]

A is the common sense choice.