Alternator whine?

negativecreep934 · #1 08-02-2005, 05:23 PM

I need some guidance on a whining sound coming from my engine. I took my 1991 accord lx to the honda dealer a few months back and asked them about the whining noise coming from my car and they said it was a failing auto transmission. On this note I started saving cash to buy a new tranny and have it replaced as some of you might note from the previous thread "installing a new tranny." I am just wondering if I should get my alternator changed as it may be the cause of the whining sound. The sound is only heard in first and second gear and gets louder as the rpms get higher. I always thought it was the transmission and had the dealer reinforce this by stating that the gears were most likely worn creating a whining sound and the jerkiness between gears. I stumpled across the whining sound being caused by some failing alternators and am wondering if there is anyway that I could check to see if the alternator is the culprite. I have checked the battery under full load and high rpms and it stays a constant 14.33 v or more. Maybe the gears in the alternator are creating this sound without any cause to the performance of the charge. I was hoping there could be some way to disconnect the alternator while the engine is running and see if the sound is not there but this may be impossible due to the alternator being connected to a belt which may/not pull other primary components. Anyway, thanks for your time.

jeffcoslacker · #2 08-02-2005, 06:47 PM

You can take the belt off and drive for a short distance without it. You water pump is timing belt driven, so it won't get hot. Conversely, you could also just unplug the regulator on the alt so it wouldn't be loaded, and find out that way also.

I'm a little skeptical of their explaination of your noise. Weak servos or bands can produce whining sounds in auto trannies, but not "worn gears" (never happens). I could see worn or improperly spaced differential gears creating a whine, but you don't see that unless some loss of fluid and overheating occur, or work was done improperly.

For the diff gears in a transaxle to run dry, the tranny wouldn't be operable, since they share fluid. So that's out.

jeffcoslacker · #3 08-02-2005, 06:58 PM

I think yours has a drain bolt on the tranny pan, making it real easy to do a partial fluid change. I'd drain it, add a quart of TransX or Seafoam Tranny conditioner and refill to spec.

Wouldn't cost more than $20, be worth trying before giving up on your tranny.

There are no gears in alternators, but the bearings do howl and whine when they start to go bad, You're right.

jeffcoslacker · #4 08-02-2005, 06:59 PM

Over-tight timing belts are known to howl like a supercharger.

jeffcoslacker · #5 08-02-2005, 07:03 PM

I just read your other post, see you tried Seafoam already...if you have slip in the gear ranges where you hear the whine, you've got worn out clutch packs or a defective servo...probably will need the tranny.

negativecreep934 · #6 08-02-2005, 09:11 PM

The other reason I suspect the alternator is because when I turn my radio on fm and a static channel I can hear a whine that rises as the rpms rise. I have read that when the diodes(?) start to go on the alternate, ac starts being produced which the stereo in the car picks up and sends the sound to the speakers like any other frequency. Maybe, just maybe, I have a failing alternator that makes a whining noise due to the failing bairings and by coincidence the whine can only be heard in the first and second gear. I am going to get an alternator off of ebay for about $60 with shipping and put it in myself. It doesnt look too difficult to install a new alt. If you have any tips on how to install it, I would be much abliged though.

negativecreep934 · #7 08-02-2005, 09:16 PM

I don't know if this helps but the whine occurs even during park. I don't know if the clutch plates are engaged during park or not.

ProMan · #8 08-03-2005, 12:07 AM

Take off the alternator belt see if the noise still there.

jeffcoslacker · #9 08-03-2005, 07:38 AM

i've seen some old domestics with badly cavitated tranny pumps that whine in park or nuetral, like a power steering pump that's low on fluid, but they were nearly undriveable.

You may be hearing the alternator on the radio, or it could just be the cap discharges of the ignition and the firing through the plug wires.

Anyhow, taking the belt off and starting it up will put this to rest.

negativecreep934 · #10 08-03-2005, 06:57 PM

ok, I'm just to lazy and don't have enough time to fool around with taking the belt off and lining it back up and so forth. Hopefully I can help with the new information I am going to provide. I turned the car on today with more of a "full" load than I thought. I didn't have the stereo on before and when I turned it on and tested the volatge reading with everything else on, the battery voltage was down to 12.31v DC. This was just at idle speed. I also have noticed when the air conditioning is turned on, the engine seems to shake more than normal, I have no idea why. I did get a new front mount recently which cured a lot of the shakes that engine used to have, maybe I need to do the tranny mount and the side mount as well. I was thinking maybe its not a failing alternator just because of the 12.3v because I did install a 400watt amp and new sound system which may be draining the current from the alternator output to 12.31v.

jeffcoslacker · #11 08-04-2005, 08:26 AM

Quote:

Originally Posted by negativecreep934

ok, I'm just to lazy and don't have enough time to fool around with taking the belt off and lining it back up and so forth. Hopefully I can help with the new information I am going to provide. I turned the car on today with more of a "full" load than I thought. I didn't have the stereo on before and when I turned it on and tested the volatge reading with everything else on, the battery voltage was down to 12.31v DC. This was just at idle speed. I also have noticed when the air conditioning is turned on, the engine seems to shake more than normal, I have no idea why. I did get a new front mount recently which cured a lot of the shakes that engine used to have, maybe I need to do the tranny mount and the side mount as well. I was thinking maybe its not a failing alternator just because of the 12.3v because I did install a 400watt amp and new sound system which may be draining the current from the alternator output to 12.31v.

That's pretty low. Minimum is usually around 13v below that there is not much charging happening. 12.3v is just battery voltage.

See what the battery reads with the car off. It probably will be about that.

The shudder with the a/c on is pretty common on 4 cyl Accords, but if the idle-up kicker is working, it should raise the RPMs just high enough with the A/c on that you don't feel it too much. I found a lot of them to be idling slightly too lean, which also causes the shake. I'm not sure what years can and can't be adjusted. You have to look on the throttle plate for a recessed brass flat screw and turn it out slowly until you have a stable idle with the air on.

In your case, excessive load on the alternator combined with a/c operation may be causing it. The alternator does drag on the motor, increasing with electrical load. Between the two it might be a little too much for a stable idle.

negativecreep934 · #12 08-04-2005, 11:54 AM

Do you think I need a high output alternator? Or, do you just think that the alternator is failing and is not creating enough voltage for the electrical components? I'm just curious because either way I am going to buy a new alternator but I dont know if I need a high output alternator or not, Any suggestions on what brand replacement hig output/alternator I should purchase?

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