Whirring noise after alternator change

[Blk 09 LTZ]

I have developed a whirring noise after replacing my alternator in my 09 Tahoe LTZ. It goes away in neutral and park, and after acceleration, but gets a bit louder when a load is placed on the electrical system(lights, heater, a/c) when in drive or reverse and brake on(idling at stop sign with foot on brake). Is there a noise filter or some other electric component I may have blown when changing the alternator; I followed all the precautions like disconnecting the battery neg terminal. The belt is like new and I’ve changed the alternator twice with the same remanufactured model from Advance Auto. The noise was not there with the original alternator which I replaced because it was overcharging.

 

[OR VietVet]

Sounds like a baring that increases enough for you to hear when under a load. Do you hear it thru your speakers or just from under the hood?

 

[Blk 09 LTZ]

It’s not through the radio speakers at all, and is less audible when I’m under the hood because of all the other engine noises, but it is there. The first replacement alternator had a somewhat rough pulley so I exchanged it for one with a nice smooth pulley, but the noise is still there, maybe even a bit more. The belt looks very good, and I’d hate to get a new belt to try if there is some electrical solution. I find it hard to believe I got another bad alternator! I can’t believe Advance could sell these if they were that faculty.

 

[OR VietVet]

Ok, I would not guess that you would get 2 bad alternator in a row. Take the belt off and see if the noise is still there when running. If it stops, it could be the belt or something being caused by both likely good alternators. There could be a ground problem that all these rigs seem to have a weak spot for. The only thing that is constant is the belt and that you changed an alternator.

 

[Doubeleive]

how did you determine it was overcharging? how old is your battery? have you checked and cleaned your battery cables and grounds?

 

[drakon543]

ive had the other pulleys suddenly go bad after doing a job like yours countless times. that or the tensioner isnt applying the same force as it used to. when you take the belt off in above suggested diagnostics prior to starting it physically check all other pulleys. spin them by hand and check for shaft play.

 

[Blk 09 LTZ]

Took the belt off and the whirring went away. Tried a brand new belt and noise still there-no difference. Then checked the tensioner and idler and both had a tiny bit of play, but not enough for me to feel it’s those. They both turned smoothly. Wouldn’t they be noisy no matter what the rpm is? The whirring only occurs between about 500 and 900 rpm, then goes away with higher revs. Took the second reman’d Car Quest alternator back and Advance mgr felt so bad, he gave me a brand NEW Car Quest unit. Guess what, same noise! And still sounds like it’s coming from the alternator...using my ears of course. The Advance mgr also verified he heard it, and was perplexed. So, would you get an alternator from a different source and ask for a refund, or, replace the idler and or tensioner and then ask for a Delco or some other brand if the idler or tensioner don’t eliminate the noise? This is getting old!

 

[drakon543]

idler and tensioner they may spin smoothly but they could be dry. also there should be little to no play in idler and tensioner pulleys. make sure you get the whole tensioner not just the pulley if thats an option. also under idle is generally when there is the most slack in the belt. under higher rpms the engine is pulling on the belt harder and can potentially make the sound go away as it adds extra pressure to a pulley.

 

[OR VietVet]

A bad pulley bearing can spin smoothly by hand with no noise until the belt tension is added and the load on that belt while running does cause a noise. I always grabbed the pulley and pressured it and moved it to FEEL some roughness.

Can you do a video of the noise and post that?

 

[Blk 09 LTZ]

Okay, I’ll try to make a deal with Advance on an idler and tensioner, on the condition that if those don’t give me a remedy, they refund the alternator and I go a different route. They DID try to help with the brand new alternator, but it’s no solution if all CarQuest alternators are junk.

 

[OR VietVet]

You gotta remember that all CarQuest alternators are not built/remaned by the same company. More than one rebuild/build company is doing them. Way too many percentages against that.

Just like GM does not make all the components that are put together to make a Tahoe or Yukon. Many suppliers make parts and put the GM logo on them and therefore GM takes control and responsibility for that part/component.

 

[Joseph Garcia]

Check Rock Auto for the tensioner assembly, as they have good quality parts, most likely an OEM option, and a fair price. As stated above, purchase the entire tensioner assembly, so that you get new bearings and a new tensioner spring.

I made this replacement a few months ago (not for whirring noise, but for a broken spring in the tensioner), and it is an easy job to perform.

 

[TheAutumnWind]

Check Rock Auto for the tensioner assembly, as they have good quality parts, most likely an OEM option, and a fair price. As stated above, purchase the entire tensioner assembly, so that you get new bearings and a new tensioner spring.

I made this replacement a few months ago (not for whirring noise, but for a broken spring in the tensioner), and it is an easy job to perform.

That would likely fix it... though I would try getting a stethoscope and determining what the actual problem is before throwing more and more parts at it.

 

[dacula789]

I have developed a whirring noise after replacing my alternator in my 09 Tahoe LTZ. It goes away in neutral and park, and after acceleration, but gets a bit louder when a load is placed on the electrical system(lights, heater, a/c) when in drive or reverse and brake on(idling at stop sign with foot on brake). Is there a noise filter or some other electric component I may have blown when changing the alternator; I followed all the precautions like disconnecting the battery neg terminal. The belt is like new and I’ve changed the alternator twice with the same remanufactured model from Advance Auto. The noise was not there with the original alternator which I replaced because it was overcharging.

I had the same thing happen when I replaced my alternator. The noise eventually subsided. Mine sounded like a turbine engine spooling up and down with the rpms.

 

[dougo]

i had the same thing new alternator change the tensioner drove me nuts tried old belts that i had as spares ( i change belts every 50K just because i can) same noise put on a new ac delco belt and the noise is gone (The old belt had less them 50K on it Not ac delco)
My new alternator was a carquest as well but the noise started before i changed the alternator so i am reasonable sure it was the belt all along

 

[Blk 09 LTZ]

Well I got a new idler as the low cost starting point, and the noise actually became a little more pronounced. So listened intently again, all around that side of the engine, and now it sounded more like it was coming from the steering pump just below the alternator. Turned the steering wheel with the engine running and the noise changed pitch up and down!

So did I mess something up in the steering pump when I took the belt off to change the alternator? And is there a fix without replacing the pump? You know that feeling you get when you feel like an idiot?

 

[wjburken]

Well I got a new idler as the low cost starting point, and the noise actually became a little more pronounced. So listened intently again, all around that side of the engine, and now it sounded more like it was coming from the steering pump just below the alternator. Turned the steering wheel with the engine running and the noise changed pitch up and down!

So did I mess something up in the steering pump when I took the belt off to change the alternator? And is there a fix without replacing the pump? You know that feeling you get when you feel like an idiot?

It would be rather unusual for someone to damage the power steering pump removing a belt, but stranger things have happened.

As far as feeling like an idiot, well, get over it. We have all been there at one time or another. This has been a learning experience for you so just chalk it up as a teachable moment.

That being said, before you jump in and start replacing the power steering pump or parts of it, get a mechanic’s stethoscope and make sure that that is where the sound is coming from.

 

[OR VietVet]

Do the scope sound check but first things first.....check the fluid level. If is low enough the power steering pump will be noisy and get louder when trying to turn.

 

[Fless]

The PS pump will probably get a little noisier anyway when the wheel is turned and the truck is sitting still. It has to work harder to turn the wheels side to side when they're not rotating forward or backward.

 

[Blk 09 LTZ]

It’s been a while since I visited here, due to a family emergency. But the power steering pump is definitely where the whining is coming from per my mechanic. He said he has the same 2009 Tahoe as mine and his has whined for years with no steering problems. He also said it’s a 2 1/2 hour job to replace the pump because you have to practically take the whole front of the truck apart, and I may as well replace the lines too. I only put about 500 miles a month on the truck, only using it to tow and haul occasionally. It’s been whining about 3 months. My questions are, how long can I expect the whining pump to last, and is there a less expensive remedy to replacing the pump?