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fire814
New User
Jan 26, 2011, 8:08 AM
Post #1 of 6
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humming when driving
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2001
Buick
LaSabre
140,00
Hi,
This noise is only when moving and gets louder and changes pitch, the faster the car is going. It is very consistant with the speed, meaning that if you stay at a particular speed, the noise doesn't change at all until you change speed. The noise is a hum or drone sound and comes from the front. Can't tell if it is from one side or from the middle engine compartment area. (my hearing isn't what it used to be...) Doesn't seem to make any differant sound when turning.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jan 26, 2011, 9:01 AM
Post #2 of 6
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Re: humming when driving
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In that it doesn't change sound when turning sorta rules out front wheel bearings but never say never. Can only guess but probably a pulley bearing on engine but engine speed and vehicle speed are NOT always the same so it probably needs a tech to listen and find the source.
As you know, noises are warnings and the earlier the fix the better. Noises travel too in cars and if hearing impaired that much harder to find the source.
Could be a tire or who knows. I know everyone wants to save a buck and the small diagnosis fee a real tech would charge could save you a ton,
T
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fire814
New User
Jan 26, 2011, 10:06 AM
Post #3 of 6
(28851 views)
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Re: humming when driving
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Thanks for your help. The sound is only when the car is moving and not when it is just sitting still. Reving up the RPM's doesn't cause the noise.
We just noticed it yesterday and I would like to find the problem asap. Think that I will start with rotating the tires. If that doesn't work, well it will might tough to find, since you have to be moving to cause it.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jan 26, 2011, 10:50 AM
Post #4 of 6
(28848 views)
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Re: humming when driving - 2001 Buick LeSabre
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OK: Now this sounds anything wheel + tire related. Take a good look at the tires for type of wear. Some will cup or scallop like saw tooth directions and make noise that sounds like a real mechanical problem. Check for owner's manual suggestions or tire maker's suggestions but most can be cross rotated and I do it to my own fleet all the time to prevent that and it does so far for decades.
Cross rotating meaning FL to RR + FR to LR vs just front to rear all the time. I write it down underhood what I did when as I suffer from CRS so need to see what I did last
If doing it yourself it's a great thing and look at brakes at the same time while wheels are off. Why not? Catching anything in advance really helps.
If rotating makes the noise move then you know its a wheel/tire issue. If the tires are worn funky as mentioned the noise will get worse and either new tires or a lot of miles to wear back to a norm if they can at all. Plain mild scalloping is not a safety issue in most cases IMO but annoying and I wouldn't tolerate it.
While up if DIYing it spin the wheels one at a time too. Feel for bearing lash which should be none. Take a general look around too.
Wheel bearings themselves near always make more noise at first turning (while driving) one way or the other as already noted.
The half shafts don't usually make a "humming" noise but there's an inner bearing too that so far I've never run into a bad one - just chance.
When bearings get bad enough they usually give what I'll call a "growl" and by the time they have any free-play it's trouble! This car has sealed bearings all around I believe so there's nothing but a total replacement if that's what is found.
I'll come back and put what type of car + year this is in subject line in a moment. Good luck finding it but do chase it down. Better to know now than make it worse or get into something unsafe,
T
(This post was edited by Tom Greenleaf on Jan 26, 2011, 10:51 AM)
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fire814
New User
Jan 28, 2011, 3:57 PM
Post #5 of 6
(28837 views)
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Re: humming when driving
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Tom, thanks for your help and taking time to answer my questions!
Well I had the tires rotated, no change. The shop said it was driver side hub. Suggested that I change both sides and while at it might as well change transaxle seals that were leaking all for $1000. Thx, I will call you later to set up appointment.
Stopped at a local small shop to double check. They only wanted $200 for one side. They did the drivers side but still had the noise so they did the passenger side also. That did it, yeah! They also said the seals were leaking much and didn't need changing. $400 compared to $1000???? I think that the first place (chain type garage) was trying to make a killing.
Jim
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jan 28, 2011, 6:55 PM
Post #6 of 6
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Re: humming when driving
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Cool so far. I'll possibly get an argument from other techs but not a believer that if one side's bearing(s) are bad then the other is too. What is concerning me is this grease you are seeing because the bearing (hub) on that car is sealed and the seal for it is to help to keep dirt and water OUT more than the grease in which is NOT re-packable. It might be grease from a CV joint boot and without any symptoms that can be monitored if and only if you wish to wait a bit. They sell the entire 1/2 shaft for this pretty cheap if that's what it is vs trying to replace just the boot it now makes more sense.
Google out these parts and you'll get an idea of both what they look like, the cost (which is wholesale not what the shop will get which is retail) and I find even if I do or don't like the place the Autozone site is quick to get pics and rough ideas of what to expect for prices.
Listen to a good tech and if they really think it's time for something to go then go for it. I'm done with doing this stuff but was at it for ages and you get a feel for what will or won't happen by a lot of factors. By the time these parts make a noise it IS time to act fast to stop any risk of a real failure. You seem to have pegged it and good for you.
Good luck,
T
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