Ratling noise from alternator (maybe)

Hi guys,

I used to have this noise a long time ago and had commented about it before

Old post here (http://www.automotiveforums.com/vbulletin/showpost.php?p=6718839&postcount=21)

Video here (http://img517.imageshack.us/img517/9035/vid00002201007121948.mp4)

It suddenly stopped and I decided not to replace anything, now it´s starting to get chilly over here and it's back!.

As I mentioned before I used to believe it was the steering pump but am no longer sure about it; I have noticed the noise will only happen under engine load (idling in gear, turning the wheels) but have also noticed that will ALSO happen during electrical load (A/C on, closing the windows specially when they have reached the top and I hold the buttons for a second). This makes me think the noise has something to do with the alternator.

Is there anything special about these alternators that could cause it? I've dealt with bad bearings but this doesn't seems like the same noise, besides a bad bearing should be a constant noise.

Any ideas?

Thanks in advance,

Oscar.

The accessory belt area on my Windstar has always been noisier than I think it should be. It's very difficult to identify where a specific sound is coming from.

I was hoping to get rid of some of the sounds after replacing my power steering pump - and discovered that the new pump is about as noisy as the old one was.

I also replaced both the idler pulley and serpentine tensioner pulley, which helped quiet some things down.

Do you have a mechanic's stethoscope? It should tell you if your alternator bearings are really having problems:

http://www.harborfreight.com/mechanics-stethoscope-41966.html

The accessory belt area on my Windstar has always been noisier than I think it should be. It's very difficult to identify where a specific sound is coming from.

I was hoping to get rid of some of the sounds after replacing my power steering pump - and discovered that the new pump is about as noisy as the old one was.

I also replaced both the idler pulley and serpentine tensioner pulley, which helped quiet some things down.

Do you have a mechanic's stethoscope? It should tell you if your alternator bearings are really having problems:

http://www.harborfreight.com/mechanics-stethoscope-41966.html

Check your camshaft position sensor and syncronizer, I believe on the 3.8 engine it is located in the alternator area.

Thank you guys,

I will do the test with a long screwdriver, I don't have a stethoscope.

I don't think is the camshaft sensor, I know it makes more like a squealing sound and it should be constant isn't it?. Mine only sounds under load specially electrical load.

I noticed today that if I hold the window (up) switch the lights will dimm and the noise will be noticeable for half a second, then the PCM will increase a little the RPM's and everything will go back to normal. Also when I have the A/C on the noise will be constant at idle and if I increase the RPM's the noise will fade away.

These symptoms make me think the problem is the alternator and not the camshaft sensor or the PS pump as I used to believe. I could also refer to the sound as a bunch of marbles in a bottle.

Oscar.

The upside of Windstar alternators: They're easy to access. After learning one or two tricks, I can change my alternator in about 15 minutes.

LOL Phil,

I wonder what would those tricks be. When I replaced the tensioner and idler pulleys along with the belt I couldn't find the retainer spring on the tensioner...

Oscar.

The tensioner pulley can be time consuming to change because access is tight. Yes, I recall having some trouble with the spring when I replaced mine.

I ended up swapping alternators in and out a number of times - and, for me, the key to a quick job is relieving serpentine belt tension without getting under the van. I discovered that, by shortening the Harbor Freight serpentine belt tool:

http://www.harborfreight.com/serpentine-belt-tool-kit-66344.html

...I can remove the belt from the alternator from the top of the engine in just a few seconds - and put it back on the new alternator just as quickly. This tool is worth the cost (and they seem to go on sale regularly).

Thanks Phil,

Actually it wasn't that hard to replace the pulleys but I do believe it could have been easier to remove the belt with the tensioner clip.

I'll see if I can get one of those tools locally!

Oscar.

Oscar -

You should be able to find one. When I first saw one, I figured it wasn't worth it - and that I'd be able to do the same thing with a wrench or socket drive. I was wrong: The combination of a long handle and low-profile head are just what's needed to make this job go quickly. There isn't much to the tool: You could accomplish the same thing using an old wrench, some scrap steel stock and a welder...

use a DVOM and check the charging system. It might drop when using the electrical items. Also check for and A/C charge on the vehicle battery directly. A diode may be out on the alternator.