Alternator going bad?

[Eckie]

I have an 04 F150 (5.4), and the past couple of weeks, I've been hearing a really strange noise from the engine...moreso as I slowly accelerate. It's hard to describe, but it's an intermittent, whirring, high pitched squeal. It's not however, like a squeal one would hear from a belt.

Seems to me it's coming from the alternator -- so, my question is, if my alternator IS going bad, what type of sound indicators would be present?

Also, I have not noticed any decrease in battery power, charging systems, etc.

Maybe I'm wrong alltogether, and will have to take it in...just thought I'd throw this towards the experts for some suggestions. Sorry for the descriptions...I know I'm starting to sound like the "lady who brings her car to the mechanic and makes all the funny noises to describe a funny sound".

Thanks...

[Jeremy airjer W]

If a bearing is going bad it can make all kinds of different noises. There can be warning signs or the can quit without warning. I like to compare electrical items to light bulbs. One minute they work the next they don't. If you have the conditions figured out to make the noise than try removing the belt and operating the vehicle in those same conditions. If the noise is not present then you are on the right track with one of the accessories causing the noise. If it continues to make the same noise than it is not related the the accessories. The water pump will not be turning with the belt off so make sure you limit your run time as not to overheat the motor!!!!!!

[Scott K]

One other thing is the p/s pump can and will whine in the cold weather. As for the alternator, it can be an electrical whine as well.

[Eckie]

Thanks, Airjer....I gotta funny feeling it's a bearing...I've had this happen on a different vehicle years ago..

One other question -- could a bearing still be the culprit if this problem has been lingering for a while (2-3 weeks)?

[Eckie]

4Wandering --- Good thought, but I know the sound of a P/S pump on the Fords...especially on the 03 and older models...(main reason I didn't buy an older one)...and, it's definitely not a whine...it's almost like a hissing, screel (screech and squeal)..

[Jeremy airjer W]

Yup! Sometimes you can spin it by hand and get a feeling if your on the right track. I would also not rule out the a/c compressor or clutch. I have been fooled by those on the taurus in the past.

[Eckie]

Could this also be the idler pulley? A friend said to be sure to check the idler pulley and belt....

?

[Jeremy airjer W]

It could be anything. I would see if it makes the noise without the belt. If it doesn't make note of which way the belt was rotating and put it back on so that it rotates the other way. If it stops making noise its the belt, if it continues than its an accessory. Sometimes you can spin them by hand and get them to make noise, other times its experience and gut instinct. Another thing you can do is at idle turn on all the accessories you can, A/C, blower on high, four way flashers, brake lights, high beams, etc. and see if it makes the noise.

[Eckie]

ok...I'm done with questions, until I get it home tonight to check it out...it's times like these I'm happy to have a heated garage!

[westrush]

I would say Idler pulley If they go it well take out the belt with it Take the belt off and spine the Idler might be more then one

[Eckie]

Upper and/or lower?

[ChuckN]

Take a wood stick or a metal bar and stick one end of the bar to the area you think is making the sound...then place the other end up to your ear and listen for distinct sounds/vibrations. When you get close to the problem spot you'll know it! Worked for me, but watch where you place the bar while the engine is running!

[trackerbrent]

It is the alternator. My 2004 f150 has been doing the same thing for about 3 years. I guess it is a common thing. It does not harm anything. Ford would not replace mine under warranty. It has been doing it now for about 36,000 miles with no ill effect. It only does it when it is 5 degrees or colder and at around 1800-2000 RPM. I think this is about what is happening to your truck. I would not worry about it.

[Eckie]

Tracker -- thanks...mine's been doing it for quite a while now...but today it was REALLY bad and REALLY loud...thinking I need to replace it. It's an easy fix anyway..

One last question -- who's a fan of remanufactured alternators? Or, should I go new and be done with it?

[Scott K]

I would only go with a Motorcraft or a new one from Ford!

[Jeremy airjer W]

Check in your area for a local rebuilder. Many times there prices are super competitive and you can ask them to use o.e. parts. There isn't a whole lot of difference between a reman and new besides the parts used. A quality reman can be just as good as new.

[PierBridge]

Lots of strange sounds during these cold snaps!

My noise calmed down today I was thinking Alt or Power steering pump.

[chanfish]

i noticed strange squeal on start up in cold weather with my yukon. it went on for about 3 weeks and then low and behold i got the one-who-thinks-I-am-silly light +/- and then it died with no juice in my driveway. it was the alternator and i replaced the belts as well.. did get reman alternator but these really cold mornings i have noticed a surge in the lights. after warmup it goes away. only when really cold. monitoring. dont know if i should take back in or not..

[Scott K]

Check in your area for a local rebuilder. Many times there prices are super competitive and you can ask them to use o.e. parts. There isn't a whole lot of difference between a reman and new besides the parts used. A quality reman can be just as good as new.

If they will use OE and not just tell you they will! I see many, many aftermarket alternators not charging, or charge light staying on with the newer pcm controlled charging systems. I average 3-5 calls everyday for this concern! They bolt on an OE, fixed!

[ilovefishing]

the easiest way to check what is causing the noise would be to loosen the belt off and hand spin the pullies, i've had to replace several idler and tensioner pullies. hope this helps

[shnelson]

I've got an '05 5.4 that does the same thing, and it's done it since I got it anytime the temps are low. I've also been told it's a common 'feature' of ford alternators to howl at you when they are cold.

I don't know if I would waste the money in replacing it if you are not experiencing actual issues, unless the noise really bugs you that bad.

[Eckie]

OK.....so last night I pulled off one of the idler pulleys (easiest way to remove the tension from the belt) and take the belt off the alternator. Gave it a few spins...and I hear it very lightly rubbing (almost like a grinding noise)...shouldn't it be almost silent?

Also, if it needs to be replaced, would one replace the idler pulleys at the same time?

[The_Duckslayer]

If it is making a very light grinding noise it's time for a new one. If the idler bearing is making a noise then yup time for a new one of those as well. If it is quiet then don't fix it if it ain't broke. Take care and N Joy the Hunt././Jimbo

[Jeremy airjer W]

The tensioner is on the left side as your looking at the truck. You'll need a 3/8 or 1/2 inch ratchet to release the tension (you should see the square hole) when you put the belt back on route it around all the pulleys except the idler, rotate the tensioner, and then slip the belt under the idler pulley.

[Eckie]

Thanks for the tip, Airjer....appreciate everyone's help...