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New faint engine whistle / grind noise

19450 Views 41 Replies 14 Participants Last post by  CruzeEcoBlueTopaz
Here is a link to an audio/video https://www.youtube.com/watch?v=1Rwt2wO3c0Q&feature=youtu.be.

This video is dark and meant to be more audio as I was searching for the source of the noise.The reason, an engine noise that recently devoloped at about 204k miles. The noise sounds simliar to a mechanical grind / whistle and seems to be emanating from the front of the engine. The noise is faint and most noticable at idle, with the hood open or at a stop and cannot be heard from inside the cabin or at a distance. The noise disappears after increasing the throttle from idle to about 1,200 and above. I suspect the cause to be an idler pulley that wasnt replaced during the install of a new serp belt / water pump at 185k . Other causes could be a vacum leek of some sort. Anyone else have any ideas ?

If it turns out to be an idler pulley, isnt it true the idler pulley can be replaced without removing the engine mount and is a fairly simple process ?
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So that is what the little fer sounds like after 204,000.00 miles on the ticker . Not bad . Let us know what ya find .
Well yeah other then this noise that recently devolped within the past week, the ticking time bomb inside the engine still sounds normal.
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Remove the belt (just let it hang so the only thing spinning will be the crankshaft) by disengaging it from the adjuster idler.

You can run the engine without the water pump spinning for a couple of minutes with no ill effects.
Start it and listen.......sound gone indicates a accessory bearing is protesting, ie, idler, a/c idler (within the a/c clutch), alternator bearing or water pump bearing.
If the sound is gone you may be able to isolate by hand spinning each component and feeling for any roughness while turning.

Sometimes, with the belt on, you can isolate by using a stethiscope with probe rod designed for this purpose.....much easier and more accurate than a screwdriver shaft with your ear against the handle.
I've seen the stethiscopes at Harbor Freight for less than ten bucks.

WAG...you likely are on track looking at the idlers.....they suffer a tough life down there and I am amazed at how infrequent failures are.

Good luck!
Rob
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Out of curiosity, have you had your timing chain replaced yet? If not you're over due to replace it.
Out of curiosity, have you had your timing chain replaced yet? If not you're over due to replace it.
It shouldn't need to be replaced...and that's not a timing chain noise (that will start to knock long before it fails).

My bet is on something in the serpentine path as well. Robby's method of removing the belt will tell you for sure, though you may have to reset check engine lights, etc. related to the alternator not charging - the dashboard will light up like a christmas tree.
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Thanks for all the valuable insight and info. I plan on bringing the cruze into the dealer to have my tech diagnosis the noise. I assume the best case sencario is a pulley that needs to be replaced. Is it true most if not all the accessory pulleys can be replaced without removing the entire component its associated with ? If so, im assuming this would be the reccomennded repair considering it would save on unnecessary and expensive labor time.

Regarding my timing chain, I was under the impression it was good for the life of the engine, allthought im sure its debateable how long that is. I replace the oil every 6k which is usually every 3-4 weeks. Also the vast % of the engines life has been at very consistant rpm's with very little downshifting. I was hoping to get at least 300k before replacing the chain and guides. Is this wishfull thinking ?
Regarding my timing chain, I was under the impression it was good for the life of the engine, allthought im sure its debateable how long that is.
My understanding of the chain is its considered a lifetime part. I have also heard around 200K it should be replaced. This interval kinda makes sense, how many miles does a person typically put on over the life of a car? probably around 200K average.

I have not seen the cruze 1.4T torn down but have seen chain guides ate to death in the 2.2 Ecotec and worn out timing chain tensioners well before 100K. On the 2.2 ecotec the timing chain was like 8-12hrs of labor so with parts around $1800-2200 a the dealer. Even at another mechanic one would pay at least $1200 for the timing chain to get replaced. This cost is cheap though considering if the chain becomes slack and jumps timing your interference engine will tear itself apart and require even more costly repairs.

Much cheaper to do the timing chain than also replace all the valves, pistons or possibly the entire engine if you wait for a failure.
Went out to start the engine because I wanted to be certain when I drop it off at the dealer and they start it up after its been sitting all night cold I wanted to make sure they will be able to reproduce the sound. I did not hear the noise. So far it seems the only time I have heard this noise is after the engine is at operating temperature.
Timing chain should be fine. Actually, your reports are good news as other EcoTec engines have had trouble with timing chains. We have heard 0 reports of timing-chain related failures on these engines, so I expect it to be just fine well past 300+ for you. I would have it checked at that point by a dealer tech - the cover can be removed and the chain checked for slop.

Making noise when warm would point to some sort of accessory bearing to me.
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Mine is making this exact noise also. Did you ever figure out what it was? I am going to stop by the dealer this afternoon and see if they can set me up with an appointment. It only whistles at idle (very low rpm). And usually only after the engine is warmed up. I only have 33k miles.
So I brought the cruze into the dealership and the tech thinks its the water pump making the noise but he cant be 100% certain. The pump was replaced within the past 30k miles. The pump will be replaced again Monday. I will know then if it turns out to be the water pump. The only other noise I can think of that would be making this noise is one of the pulleys on the belt.
Hi dan200615,

We are sorry to hear that you are also experiencing this concern. I'm glad you'll be taking it in to the dealership, I hope you'll keep us updated!


Andraya R. (assisting Kristen)
Chevrolet Customer Care
Hello CruzeEcoBlueTopaz,

We are glad to hear you dealership was able to address your concern. Hopefully that will fix noises you were experiencing. If there's anything we can assist you with on our end, please send us a private message!

Andraya R. (assisting Kristen)
Chevrolet Customer Care
Water pump was replaced under warranty and the noise is gone.

I am a little concerned after the repair I checked the cold coolant level and the reservoir was almost completely full. I hope the coolant system was completely purged of air. I will have to use a suction device to remove excess coolant to the normal fill mark.
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The excess coolant will vent out in a couple of thousand miles, assuming you don't mind breathing it while it does it.
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Im going to remove some coolant it shouldnt be full. I also plan to remove the reservior cap and let the engine warm up a bit and watch for small bubbles just to make sure most if not all the air was purged during the install. Im confident in my dealer agent and tech im sure he followed gm proceedure.

Everyday when traveling a 1 mile 2k ft elevation climb coolant temps will start to rise from 219F normal to 225F when I start the ascent which is about the time I start to smell the vapor. Coolant temps can reach 235F near the top. Somtimes the cooling fan turns on right away and prevents the coolant from getting aboove 225F sometimes it doesnt turn on until about 235F but when it does the temperatures drop quickly to normal and below. My point is everyday I usually smell coolant vapor for about 10-15 seconds at about the same spot on the mountain when the coolant reachs a certain temp and its the only time I ever smell coolant.

Not a big deal at all im just happy to have a new pump and no unusual engines noises. This noise from the engine certainly did get me thinking about wanting to replace as many belt pulleys as possible in the near future.
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Getting my Cruze back after work, the service team called me and said the water pump bearing was bad and making the noise. I mentioned the water pump when I brought it in so they had a good idea where to start looking. One more reason to love this forum!!

I will check the coolant level too when I get it back. Hopefully it is at normal level.

Thanks for the thread CruzeEcoBlueTopaz... I hope it helps others like it has me!
You're right, the tank should not be over filled. Also, you don't need to run the engine with the cap off to purge air, the system has a small "steam"'pipe for that, the small coolant line that attaches to the top of the reservoir.

One thing you should do is make sure the rad is purged of air. There's a small bleeder screw at the top of the passenger side radiator tank, it's white plastic and accessible with a short flat blade screwdriver. Undo the bleeder slowly, this will let any air out of the top of the radiator. If you really want to do it right, park the car so the passenger side is higher than the driver side. As soon as a small amount of coolant comes out close the bleeder. Note if the coolant level in the tank dropped at all.

The dealer tech should have done this, but it would be easy to forget. Once that's done, drive the car for a few miles and make sure to rev it up to 3-4k RPM and hold it there a few times. At this point let the car cool down, and you may even wish to repeat the rad bleeder process again in case any trapped air made its way into the rad. Top the tank off (or lower) to the correct level and keep an eye on it for a few days.
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BTW, I've never heard of a timing chain that was designed to be a wear item, they're always designed to last the life of the engine as far as I'm aware. No worries.
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