I have a 2001 Monty Carlo 3.4 LS. Under acceleration (pulling on to a highway) I get a squealing noise under the hood from the passenger side of the motor. If I ease off the gas the squeal stops. I have replaced the belt, tensioner, pulley, water pump and alternator. The only things I have not replaced are the power steering pump, air conditioner compressor and the crank pulley. Anyone got a solution. It does not seem to affect the vehicle but it is annoying.

 

Welcome to the forum!

Maybe.. its the wrong tensioner allowing the belt to slip...or the belts to big to take up the proper slack with the tensioner?
Im sure someone else will chime in with more ideas.

 

Sounds like you hit a bunch of things trying to find this squeal. Despite what you have changed, here are my thoughts:
- With the car in the in park and running, listening under the hood, can you hear the squeal? If you hold some higher RPMs, can you here the squeal?
- Car off, remove the belt. By hand, spin each pulley one at a time. Listen for anything "odd" in the rotation sound. Also, feel if there is anything weird about the rotation.
- With belt off, wiggle the pulleys. Look for "slop" or "play" in them.
- If the answer to the first question was "yes", then with belt off and nothing in the way of any pulleys, start the car, repeat what you did in step 1, but with no belt. Do you hear the squeal? If not, then there is something faulty in the belt drive (pulley not aligned with the system or a bad pulley/component).

- If after all this, still, no sign of noise, lets assume it's NOT engine related. Jack the front wheels up. Time to invest investigate both brakes and wheel hubs (since the noise is at higher travels, my guess is hubs, brakes are more consistent).
Note: You want to check both sides, sometimes where it sounds like it's coming from in reality is not what you thought.
- With car in neutral, rotate the tires by hand. Do you hear any noise? Typically, if it's brakes, you would here it in this test.
- Wiggle the wheel. Start by holding top and bottom and wiggle. Then left and right. Typically, that's enough, but I like to also go across diagonally (if you find play, it will happen in ALL directions of wiggling). If there is play only wiggling left and right, this can be a tie rod or pushing to hard and it's moving the steering rack. If you suspect tie rod, you can turn the wheels and get a look at the tie rod while wiggling the wheel. If there is ANY play wiggling in all directions, you found you problem of a failing wheel hub bearing assembly. At which point, MCF has write ups about changing that out. I would highly suggest a Timken bearing hub, it may be a little more cost but it has AWESOME reliability.

- If you still have not found the source with these tests, you can inspect the brakes further (but again, if you don't hear a noise at all spinning the wheel by hand, then it is probably not the brakes, but you're this far, pull the wheel off and see if the warning tabs are rubbing the rotor).

I hope this helps find your problem. Some how, I have an odd feeling it's a wheel bearing hub assembly.

FYI - Sometimes a failing hub noise can go away and come back by slight steering wheel movements. When you hear the noise you can also try tilting the wheel just a couple degrees to the left and to the right, listen closely if the noise changes at all. Make a note of what way you moved the wheel that resulted in changing the noise and how the noise changed.

 

Thanks for ideas. Here is what I have found. I can create the squeal will parked in the driveway, so I removed the belt and tried it. I am able to create the squeal with the belt removed so it has to be an engine noise. I have so far checked all the hoses and they are in good shape I am beginning to think it might be an ignition coil pack.

 

Thanks for the ideas. The squeal can be duplicated while the vehicle is in park. I removed the belt and was able to duplicate it also. RPM have to be up around 3000. I have check all my hoses and they all appear in good order and no leaks so I am beginning to think it might be an ignition coil pack.

 

i have a 96 monte with the same squeal. if it happens when you sit still and accelerate, it might be your ac pulley.


on mine it'll keep squeaking because i dont have the ac unit on my car since i put another engine in. the guy put belt ease on it...and it stopped....for a minute.


so its just a free spining wheel and my god is it irritating.


i hope you get this fixed soon, from one car owner to another

 

i had this problem b4 and the problem was that while i was servicing my car i got oil on the underside part of the belt which got on the the pullys....basically what i did was take a lil degreaser and wiped down all of them, i.e. a/c pully, power steering pully, altenator pully...etc.

 

It would be strange for it to be a coil, but I know sometimes electrical parts can make weird/unexpected sounds. To easily rule out coils, if you have access to another GM car with a 3100, 3400 or 3800, you can easily swap the coils and see if the sound follows the coils. FYI - If it really turns out to be a coil, I recommend buying a salvage set. I have yet to be impressed with aftermarket replacements and since stock ones rarely fail, I would not hesitate at getting some salvage ones.

What might be better to check is for a vacuum leak. If you have one small enough it may not hold much of a performance issue but could be making that squeal. Cheap test for that, mist starting fluid around the engine while it's idling. If the engine changes sound, focus in that area until you find the vac leak.

 

Maybe its a leak somewhere in the exhaust manifold. Ive seen a cracked manifold that was vibrating the heat shield and making a high pitched whine

 

I can tell you right now that it's not the ignition coil, they do nothing that can make any noise except for a crackle, because they only supply electricity to the distributor, which in turn gives spark to the cylinders (or for your modern engines it supplies a short burst of high voltage electricity to the cylinders - the spark).

You have a bad bearing or somebody was telling me it could be the cam sensor "driveshaft", because it gets very little lubrication - he also said he had this problem on both his '04 Monte Carlo and his Ford Focus.