whining sound from engine compartment

[hawkeye1956]

01 Impala with 3.8, and with 95000 miles just developed a whining sound that appears to be coming from one of the components connected to the serpentine belt. From searching this forum, it appears that the fuel pump can cause this whining sound in some instances and the noise can travel down the fuel lines which causes the sound to appear to come from under the hood. The whine increases in volume with higher RPMs. It is not noticeable at idle. To troubleshoot, I removed the serpentine belt, started the car and ran up the RPMs and observed that the whine was gone. I started checking the various pulleys and it appeared to me that the bearings in the Alternator were bad, although I was not sure. I took the alternator to two different parts houses as nobody seemed to have the part and both confirmed it appeared to be bad alternator bearings. Eventually, I obtained a rebuilt alternator, reinstalled the serpentine, but to my disappointment, the whining sound was still there. I had my wife rev the engine while I listened in the trunk with the back seat folded down but could not pick up the whine anywhere near the fuel pump. My fuel filter was replaced about 25k miles ago. I know that power steering pumps can cause this but is more typical only when turning the wheels and with low fluid levels. I would not expect engine RPMs to affect noise from a power steering pump. At this point I am reluctant to change the fuel pump as it is fairly expensive and I am not at all sure this would fix the problem. Would reducing the engine load by removing the serpentine cause the whine to go away if it were the fuel pump? Any suggestions would be most welcome as I am close to biting the bullet and taking it in.

[mocha1234]

Hello,

I have a 2001 Impala LS with the same issue. Started a few weeks ago, and has gotten worse. I have replaced the accessory pulley assembly, the entire unit. Took about 2 hours from start to finish and also replaced the serpentine belt with a new one. Still squealing after about an hour or so of driving. Have heard on line that people have replaced the water pump also with no resolution.

Have had issues with the intermediate steering shaft, replaced 3 times in 3 years. Had an issue witht he fans being on 2 times in the last two years. Was able to resolve this issue with a new thermostat from the dealer, the stant will not fit correctly. They end up costing the same price, which is a surprise.

A lot of glitches come along with this car. This is the last time I buy an american car ever. Too many problems.

If you find out the resolve for the whining, let me know. My friend who is a mechanic is going to look at it for me saturday, if we resolve it....I will send along an e-mail.

Jason C

[pistonring]

Have you tried using an engine stethescope to locate the noise? Maybe that could help?? They are inexpensive at about 15 bucks.

[crazy Jim]

First thing, I'd determine whether or not it is the belt itself. Rough up the back side of the belt to quiet it down or purchase a Gatorbelt. Next, check for low fluid level in the power steering resevoir. Third item would be the idler pulley. One of these three items will be the problem.

[mocha1234]

I have tried replacing the belt, the pulley assembly, have checked the power steering reservoir. Everything is normal.

Thanks for the response.

[crazy Jim]

Originally Posted by mocha1234

I have tried replacing the belt, the pulley assembly, have checked the power steering reservoir. Everything is normal. Thanks for the response.

the idler pulley? Also, replacing the belt does not necessarily mean that was not the problem. I changed the belt on my GMC 8L truck engine and the new belt made the same squeal as the old (original) belt.

[gw84]

my '93 3.1 lumina whines as well. However mine seems to be from the transmission. It whines until you get up to 20mph. When the car shifts the whine stops. Have you noticed anything similar with your impala?

[mitch_houser]

ive had same problem lately i checked power steeering leval fine also took belt off cracked engine still there .not in alternater,tention pully, power steering pump, ac hope its not in fuel pump they cost jack and are hard to get too

[richtazz]

If it was the fuel pump, the noise wouldn't have went away when you took the belt, nor would it change with engine RPM. Engine RPM will affect the noise from a p/st pump, because it is driven by the engine. To confirm that your new alternator isn't the culprit, unplug the connector at the voltage regulator and start the car. If the whine goes away, it's the alternator making the noise. If the noise is still the same, then the power steering pump is most likely the cause.

[3rdChevynow]

My 2001 3.8 9C3 Impala used to produce the whine sound during a hard acceleration. The problem was fixed after the two original suspension bushings of the dog bone engine mounts (at the frame ends) were replaced with the Polyurethane ones bought from this link:

http://www.3800performance.com/Merch...roduct_Count=0

It was discussed in this site that the original bushings allowed too much room for the engine to move during a load.

However, with the polyurethane bushings, the car body vibes a little more than usual, during idles.

Hope that help.

James

[3rdChevynow]

I have replaced the two front motor mount bushings (frame ends) with the polyurethane ones ($69) bought from http://www.3800performance.com. It fixed the problem of whining sound produced during a hard acceleration. I have a 2001 3.8 9c3 impala.

Hope that helps.

James

[hawkeye1956]

Well, it certainly appears that there are lots of root causes for a whining Impala. It finally warmed up enough here to work on the car again and in my case it was indeed the tensioner pulley. I lucked out this time to be sure.

I also agree with whoever suggested to replace the original belt with a gator belt. I neglected to mention that I did that on round 1 of troubleshooting.

I have already experienced many of the problems mentioned in this thread such as fans running all the time due to a partially open thermostat, fuel pump problems, and power steering pump noise. The power steering fluid being low makes me believe I am headed for problems here but time will tell. Contrary to what someone said, the fuel pump is very easy to get to through the trunk but it is not a part you want to replace if you are not sure it is faulty.

Thanks to all who posted suggestions.

[mitch_houser]

So if my belt was off and the noise contiues to stay the same,its not any of the componets? then what ive bought scope tryed for the fuel pump deal no extra noise comming from there at all. andone more thing ive got a code for EGR flow insufficient took to shop guy tells me EGR wornig fine is ther a sensor for that ?that tells EGR what to do cause he controlled EGR said it responded corretly to every thing he told it to do just wondering thanks mitch

[richtazz]

the PCM gets it's vacuum signal from the MAP sensor, which is located in the end of the upper intake plenum near the alternator. The noise you are hearing may be a vacuum leak a the MAP sensor housing. When you remove the map sensor and the plastic piece it sits in, there are 2 o-rings, one large orange one at the top, and another around the base of the PCV valve (as well as spring that holds the PCV down). Many people don't see the lower o-ring on the pcv valve and inadvertently throw it away when changing the valve. If one or both of these o-rings is missing or damaged, it would cause both the noise and the EGR insufficient code to pop up.

[mitch_houser]

thanks rich im going to g obuy new o-rings tomorrow and try that out cant be too much cost ive had the map sensor off to clean so ill replace the that one and the 2 in the pvc area also hope it works thansk mitch