Glowing altenator

2000 Ford Explorer XLS V6 5.0L SOHC. 149K miles.

I started the truck with the hood open and noticed a light in the engine. Looking closer to see whats up its the altenator. The rear of the altenator is glowing, bright enough to notice. I have no charging system issues, the altenator is charging normally. It's the original altenator so i'm expecting having to replace one soon but my question is:

Is there any danger in not replacing it right away? Should I replace it immediately? Anybody ever seen this before?

Is the rear bearing overheating and glowing or is it an electrical glow.
Either way I would replace it I would suggest going to an alternator rebuilder and finding the cause.

Alternators are not supposed to glow. Since it's an OE i would say you got the most out of it. Alternators fail at stages with some part of it going bad before total failure. Even though it still operates you will still need to replace your alternator soon. The danger would be a fire or an electrical fault that would disable or at worse destroy your fine truck. I would go back with ford (MotorCraft). They are the best. It gave you almost 150k of electrical bliss!

I have no clue whats glowing. the rear of the unit is lit up. if it is the rear bearing then what? if it is an electrical glow then what? other than replace it, how long will it hang in there?

Alternators are not supposed to glow. Since it's an OE i would say you got the most out of it. Alternators fail at stages with some part of it going bad before total failure. Even though it still operates you will still need to replace your alternator soon. The danger would be a fire or an electrical fault that would disable or at worse destroy your fine truck. I would go back with ford (MotorCraft). They are the best. It gave you almost 150k of electrical bliss!

yea i know. just wanted to hear some opinions on the issue. this truck is one of the good ones. still has the same engine, engine components, and tranny that it had off the assembly line...we bought it brand new.

Glowing = heat, and lots of it. If it's electrical heat, then it's only a matter of time before the insulation melts and wires short out which would likely cause a fire. If it's a bearing or other mechanical interference, the heat will burn away any remaining grease in the bearing and eventually it will seize up, causing the alternator to stop turning, the serpentine belt to slip and burn up, leaving you stranded. And the heat from the hot bearing could also cause a fire.

If it's truly glowing, then I'm surprised it's still going. I would not trust it to get you out of your driveway. That's not to say it won't, I just wouldn't be expecting it to.

-Rod

Whats up Rod,

I took a closer look...moved some wires out of the way. The hot cable/contact on the back of the alternator has melted away its rubber cap, or the cab broke off from becoming brittle. What im seeing looks like electrically charged debris (the cap) getting grounded...touching both hot contact and the altenator case. Strange because im fairly certian that plastic is not a conductor of electricity but for some reason its getting hot like an ember and glowing orange. I got most of it off and the glowing happens now for about 5 seconds after the engine is started then goes out so there must be more back there. before i cleaned away some of the debris the glowing was fairly bright and constant. The insulation on the hot cable is also missing about an inch back from the connector. Im going to have to pull the altenator and get it all cleaned off and then either re-insulate the cable or replace it.

I my concern is whether or not the plastic around that cable was melted away or whether its breaking off from becoming heat brittle like much of the plastic in the engine compartment.

With the mileage and age of the vehicle it just turned brittle. Repair/replaced as needed.

If you try a scrap yard you might be able to purchase a complete section of cable to the alternator in good condition.

Finally replaced the alternator today. When I pulled it the post attached to the hot cable broke right off. Never seen that before. The cable itself was brittle as well. Luckily it was long enough that I couold cut off the bad cable and attach/crimp another connector to the end of it. Why did that thing get so hot in the first place is a mystery to me -- or maybe its because it was the OEM alternator or something. Maybe something is going on elsewhere?

Anyway

Maybe that connection was bad before and the resistance to current flow was causing the heat.

-Rod

ok, what do you thing about my post about the engine stalling? Looking forward to your advice on that post.

Ever had the throttle body cleaned/lately?

please see my 'Engine Stalls' Post...