Rough Idle? Also Buzzing Alternator question?

https://www.youtube.com/watch?v=uXrS5VW4Vl8

I've recorded a video of it buzzing and you can also slightly hear some sort of rapid clicking too, but mostly the buzzing is my concern.

This is the car that had the reverse switching to drive stalling issue. I replaced the IAC valve and boy howdy I can hear the difference in the start-up. But then my car also was running into a misfire on cylinder 4 that threw a blinking CEL at me along with a p0304 code. So I started with the checklist, replaced the spark plugs, and the coil pack, yet now my car is rough idling and probably is still misfiring. I'm too chicken to try driving it to see if the code will pop back up because I just dont' want to hurt my car more.

The only things on my checklist left to replace is the EGR Valve, and my alternator's been buzzing pretty loudly as demonstrated in the video.

I'm not sure if at this point I'm just hyper-sensitive to a noise that was already present, or if something is going wrong on the alternator now too.

Do you think my next step to try and correct this rough idling should be replacing the alternator, replacing a part on the alternator, or replacing the EGR valve? Am I just being hyper-sensitive to the alternator's noise?

I don't have many tools at my disposal and I'm not made of money and in fact can't afford much in the coming days because work hours got tanked, but something for me to plan for anyway would be nice. Any and all assistance is invaluable to me right now.

Quick thoughts:

- If the alternator really is making most of that noise, it's most likely bearings that are failing within the alternator. Replacing the alternator will fix it. Thankfully, Windstar alternators are reasonably priced, have good access and are easy to replace. Note that my experience is on my '00 3.8 Windstar, but your 3.0 Windstar's alternator appears to be mounted in the same manner.

- Make sure it really is the alternator that's making this noise! One quick method: Remove the serpentine belt and spin the alternator by hand. Do you hear the same kind of noise, and feel harshness in the alternator shaft and bearings? Then it's time to replace the alternator.

- Note that the idler pulley is below the alternator pulley. Failing idler pulley bearings can also make this noise. Again, just spin the pulley by hand with the serpentine belt removed. It should spin smoothly, without excess play. Idler pulleys are pretty cheap and easy to replace.

- Another item: The power steering pump is right next to the alternator. In my experience, Windstar power steering systems tend to be noisy. I replaced my power steering pump - and even the new pump was pretty noisy. I've found that periodically changing the power steering fluid is a good way to quiet the system, and help it run smoothly. I use Mobil 1 synthetic ATF; check your owner's manual for appropriate power steering fluid options for your vehicle.

I agree with phil-l. I'd strongly suggest that you rule out the power steering pump. This sounds a lot like how a bad pump sounds.

https://www.youtube.com/watch?v=BD3PTy2B1EI

You should be able to isolate the noise by checking each bearing with a stethoscope tool, or a hose with one end in your ear and the other pointed to the location.

You can get the effect of the stethoscope with a long socket extension or breaker bar (or any other convenient metal shaft). Put one end to your ear, the other end on the part. You can normally isolate bearing noise this way.

This one for $4 has worked very well for me on several occasions.

https://www.harborfreight.com/mechanics-stethoscope-69913.html

I highly recommend picking one up for instances like this. It will help you quickly determine the source of the noise.

Thanks for the replies guys,

As for power steering noise being one of the possibilities, while I'm not ruling it out completely already, I will add that I know how noisy the Ford power steering can be. I can typically identify the sound of mine and one thing I forgot to mention with this buzzing noise, is with the car in park, I'll rev the motor up to about 15-20 mph, and the noise quiets or smooths out somewhat.

And during the video recording I didn't move the steering, so I would assume the power steering to not be one of the problems, at least not the one giving cause to the rough idling that is my main concern next to this buzzing noise.

Do you think the bearing is going bad in the alternator if the noise smooths out when I rev the engine? The rough idling seems to smooth a little as well while this happens, and when i let off the gas it returns back to its rough idling and buzzing noise from the alternator.

I will, as an aside when I have the money once I fix this rough idling/buzzing noise, is get the power steering fluid flushed and replaced.

It's hard to specifically identify alternator bearing problems based on noise alone (well, unless you use the mechanic's stethoscope mentioned earlier - I have one, too!).

It only takes a few minutes - and a few basic tools - to remove the serpentine belt. Now you can spin the alternator (and idler pulley) by hand. You should be able to feel what needs to be replaced!

Just like the alternator, the power steering pump turns (and therefore pumps) even if you're not turning the wheel. However, I believe the pump does have to work harder if you turn the steering wheel. Power steering pump will definitely make a buzzing noise at idle without turning the steering wheel.

As far a engine speed effect on the noise, I don't think you can use that to conclusively diagnose the location. That said, a slower turning alternator will generate less power, and therefore will resist the serpentine belt little bit more than a faster turning alternator. That resistance might make a noisy bearing stand out.

The stethoscope test is easy even if you don't have one (using an extension, pry bar, or other metal rod). Alternatively, you can pull the alternator and have it tested at an autoparts store. They can verify the bearing noise during that test.

I'm going to chime in on the difficulty in determination of noise source on the serpentine belt line. I spend many hours and parts chasing this down......mine would ONLY make the noise at a certain RPM.
If you remove the serpentine belt and spin each item by hand....you MIGHT be able to track it down.
I found my tensioner pulley bearings right away this way.
In my case, the difficult one was the idler pulley, but I think MOST cases will be easy to tell with these pulleys.
The pulley units are cheaper than the water pump, alternator or power steering pump.......or A/C compressor.

The bolt holding the idler pulley was a real bugger to break free.....took some serious abuse to get mine loose.

Power steering.....periodic replacement of the power steering fluid (use transmission fluid) is advised.... Any air bubbles visible in the fluid when you look in the reservoir are bad.....air bubbles in the power steering fluid WILL make a nasty racket.

Alright, thanks for further clarifications on all fronts!

I shall work towards diagnosing the source of the buzzing, either by taking the belt off and spinning each pulley by hand to try and see if one comes back with resistance.

I'll also be checking the power steering fluid for bubbles. I DO remember over the summer I think it was I had my car worked on and there was a LOT of power steering fluid. Like, so much so that taking off the cap and it seemed ready to overflow. I never got around to sucking some out with a turkey baster, but I'll probably do that if it's still full when I go to check it next time.

It might be a while before I'm able to work on the car as it's due to rain here soon and it's pretty cold, but I will try to report back my further findings when I do!

I'll also be checking the power steering fluid for bubbles. I DO remember over the summer I think it was I had my car worked on and there was a LOT of power steering fluid. Like, so much so that taking off the cap and it seemed ready to overflow. I never got around to sucking some out with a turkey baster, but I'll probably do that if it's still full when I go to check it next time.


A little note on this with the caveat that my experience is with the 3.8L so this may not apply: The reservoir (in the 3.8) has a fine screen towards the bottom that, over time, gets plugged with carbon gunk. It took me a while to figure out that issue but I had to remove it and spray some carb cleaner to clean it off, and that cleared up ALL my power steering issues. Again, I do not know if the reservoir in the 3.0L has that, but it may be worth checking. (siphoning out the fluid with a turkey baster should answer that question pretty easily.)

Did you ever figure it out mine turned out to be my tensioner.