Help with engine noise, video included

wormwood1978

Registered Member
Original poster
Jan 3, 2015
54
2008 Trailblazer 4.2, 85,000 miles.

I noticed this noise about a month ago when idling but also when the gas pedal is slightly touched. The noise is more noticeable on the passenger side. In the video you will hear the chirps at 3-5 seconds and 24-40 seconds. Any ideas? **I had my wife rev the engine a couple times during the video

I just changed the belt, tensioner and idler pulley and that changed nothing on the sound. Original water pump, fan clutch, ac compressor and power steering pump. When I had the belt off, none of the pulleys seemed off. Also, my power steering seems good and no groans when turning the wheel, although the sound, the chirp if you will, may be coming from somewhere near the power steering pump area.



 

xavierny25

Platinum Donor
Mar 16, 2014
6,111
Staten Island, N.Y
The noice does point toward the power steering pump. What brand parts did you go with for tensioner and pulley? Does the sound change when you have the ac running?

Edit:Which belt did you use?
 
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Blackstar

Registered Member
Aug 2, 2014
90
Sounds like power steering, like xavierny25 said. But mine makes a whine sound since it was changed several years ago during a steering rack change. But mine is a higher pitched sound. Could it be your alternator with a bad bearing?
 

MRRSM

Lifetime VIP Donor
Oct 22, 2015
5,714
Tampa Bay Area
@MAY03LT 's Video for this diagnostic which revealed the Alternator as the Culprit... but notice how he also spins the Power Steering Pump Pulley as well... Might be worth comparing what his sounds like to your own:

 
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gmcman

Guru
Dec 12, 2011
4,526
Some of these power steering pumps had a noticeable whine, albeit slight, not sure about later models. I could hear yours whine at 36-37 seconds, and I did hear the chirp also.

What is the power steering fluid level?

I would remove the belt and check the water pump, power steering, and alternator.

The water pump will make a hellacious noise when starting to go bad, but check for excessive wobble in the water pump, try to turn the water pump/fan pulley while applying pressure to the pulley and see if it makes any scraping noises.

Check the power steering pump for wobble and it should turn freely.

Did you have the AC on? If so, that could be one reason there was a chirp if the belt is the wrong size.

Do you have the old belt?

Sidestepping here slightly... Just some helpful advice, it would be advisable if you don't already do this, to keep the old belt and a 3/8 breaker bar in the cargo area in case you ever lose your belt on the side of the road.
 
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wormwood1978

Registered Member
Original poster
Jan 3, 2015
54
Power steering fluid level is good and annually for the past several years, I have sucked the old fluid out and put new in.

The tensioner, belt and idler pulley that I used were Dayco (kit 5060915K1) . The old belt was Gates (K060913) but only had 4 years on it and maybe 30,000 miles. I'm keeping it as a spare.

I did not have the AC on.

With the belt on, engine running and hearing the noise, I used a mechanic stethoscope but could not isolate the noise to a specific part. I also ran the engine without the belt and did not hear any noises, meaning belt on noise, belt off no noise. Spinning each of the pulleys did not point to anything either. Based on where I think the sound is coming from, I suspect the power steering pump. With that said, I would have expected some other problems such as making noise when turning the wheel, or a fluid leak or something.
 

gmcman

Guru
Dec 12, 2011
4,526
Try again with someone turning the wheel...if you haven't already.

I did hear a pump whine at 36-37 sec into the video.
 

gmcman

Guru
Dec 12, 2011
4,526
Ok, I listened again on better speakers and at 36-37 sec it sounds like you revved it slightly. Different pitch coming through smartphone speaker.
 
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wormwood1978

Registered Member
Original poster
Jan 3, 2015
54
I did also hear the slight groan you mentioned separate from the chirp. The groan is not something I have noticed before as I have been regularly hearing the chirp.

As suggested I had my wife turn the wheel back and forth and it does not reduce or increase the chirping. I am almost certain the chirping is coming from the passenger side, kinda in the area of the power steering reservoir. The power steering pulley may be making some noise since I am concentrating on it now, just not certain if the noise is normal spinning or not. I just wish I could pin point the chirp.
 
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wormwood1978

Registered Member
Original poster
Jan 3, 2015
54
Solution: New muffler.

I was very close to throwing parts at my problem starting with a new power steering pump. My annual state inspection was due and before they would give me a sticker, they wanted a new end link and a new muffler. They said I had holes in my muffler. Anyhow, I did the end link myself and looked closer at the muffler. Yes some rust, yes original and yes it might quiet my vehicle some, but no holes. I had them do the muffler and now no more chirping and my vehicle is quieter. The chirping I was hearing I thought was somewhere near the power steering reservoir or near the exhaust manifold, I guess it was exhaust related.
 

gmcman

Guru
Dec 12, 2011
4,526
Just throwing this out since you replaced your muffler. I tried a Walker Quiet Flow a few years ago as my muffler had some holes in it I went with the muffler and the resonator and soon found out my MPG dropped about 2 MPG, also had twice the back pressure.

The inside of the muffler was reduced in size quite a bit, probably lost a good inch in total ID. Some mufflers have been reported to be good, but not this one....for me anyway. I found a good exhaust from a boneyard and swapped that back in.

The stock exhaust is hard to beat for overall flow, just keep an eye on your fuel economy for awhile.
 
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wormwood1978

Registered Member
Original poster
Jan 3, 2015
54
Just throwing this out since you replaced your muffler. I tried a Walker Quiet Flow a few years ago as my muffler had some holes in it I went with the muffler and the resonator and soon found out my MPG dropped about 2 MPG, also had twice the back pressure.

The inside of the muffler was reduced in size quite a bit, probably lost a good inch in total ID. Some mufflers have been reported to be good, but not this one....for me anyway. I found a good exhaust from a boneyard and swapped that back in.

The stock exhaust is hard to beat for overall flow, just keep an eye on your fuel economy for awhile.

The muffler was replaced with a Walker Quiet Flow. I will have to keep an eye on mileage. Thank you for pointing that out!
 
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wormwood1978

Registered Member
Original poster
Jan 3, 2015
54
And just a follow up to this. My one year old Walker Quiet Flow muffler is going in for a warranty repair one year after install because it has a 12" leak in it along the top to bottom seam. My local shop found it after chasing down a noise I had only when accelerating which turned out to be the exhaust gasket between the catalytic converter and the exhaust manifold flange.
 

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