hizzo3

So I was working on replacing both heater bypass hoses and noticed this sound. Barely can hear it inside the car unless the radio is off, windows down and parked right next to a wall. Doesn't seem to get louder with engine rpm. Only starts once warm (gradually). Ideas?

FearOfSilence

iTrader: (1)

Do you have an idea when this started? Did you have any other work done to this recently other than when you you replaced toughs hoses? Based on the noise, I seems to be the loudest somewhere around the top of the engine. From passed experiences of similar engine whines on these engines I have seen the tension on the water pump balance shaft chain to be too tight causing it. That usually however ends up happening because the water pump was replaced. That being said though that noise would also generally increase with engine RPM as with most internal engine noises

I would take the oil cap off and verify if it get louder with it off. If it does its probably something in the engine if it does not then it may be something around that area. You can use a screw driver like a stethoscope touch a component with it an put your ear on the handle and listen for the noise to become louder. probe around and it should give you a general idea where it might be at. you might also be able to feel the vibration by touching the component just keep your hands clear of moving components.

Hope this helps

hizzo3

Recently, as in the last month.

ZZP mid headers and cat. Still haven't tuned it. Waiting for the intake, muffler and custom over axle pipe.

Water pump is the stock unit. I got the car with 6k miles. At 87k now.

I'll try and do more diagnosing when I get a chance. At first I thought it was a coil about to go because I first thought the whine was electrical high frequency.

FearOfSilence

iTrader: (1)

None of that stuff should have caused the noise to occur. In all the years i have worked on these Ecotec engines I have never heard a coil make a noise like that. I am not going to say that it is not possible because I have heard electrical high frequency noises like that before too just not so much on these cars. let me know if you come up with anything. I will try to help out the best that I can.

hizzo3

Thanks. I was hoping it would be something straight forward. I'll start with the normal diagnostics. Oil change, look for metal shavings, pull the valve cover and inspect the cams and valvetrain, replace the adjuster while I'm in there. My brother is a mechanic so I think he'll lend a hand. Hopefully if it is something mechanical, its just in the valves.

umrdyldo

iTrader: (1)

That's is the craziest sound I have ever heard.

Congrats. Does it sound metallic at all? Because it doesn't sound like it in the video.

Sounds like you have a geiger counter under the hood.

Cman46290

I 100% agree.... most odd noise that ive ever heard.....in almost 10 years of being in the car game.... it sounds like a REALLY annoying alarm or something.

Odd that when you move away from the VC/middle coils the noise almost is non existant.... you pull the coils/plugs to check them out? or the oil cap off while running to see if the noise was coming from the head?

hizzo3

Not that I can tell, if it is, its a high rotation. Brother says it sounds like a dremel. I've done lots of electronics work, and the high frequency noise is what it reminds me of (think old camera flash charging). Or the 2000's 'burbans when driving.

Haven't checked the coils yet. Gonna plug in HPT tonight to search for codes (I have a CEL from the header, not sure if others popped up) and check oil pressure. My brother (who is a mechanic and has an HHR-SS/TC) says it sounds like the tranny is resonating through the block, but I don't agree. If its not the coil packs, I'm going with it has to be one of the cam bearings, but the sound should be lower frequency.

nhanson

iTrader: (1)

I would move coils around and see if sound follows.

hizzo3

Looks like issue solved. Cyl 3 plug backed out, breaking the coil boot. The sound was the cyl pushing its contents past the plug. Cyl looks pretty nasty inside. Gonna clean the plug, new boot, run some seafoam to clean the cyl, then new plugs. Coil was shorting to the block, so hopefully the coil is in good condition.

I figured it was the coil because when I touched the coil, the sound changed. Upon removal, it was evident what had happened. DTC's were reset by mistake fixing a blown fuse for my CIG lighter so I could pull the codes. Probably a rich condition. Hopefully the CAT is still good. Its the zzp one so I hear they hold up well.

Awaiting parts to fix.

FearOfSilence

iTrader: (1)

Wow, That is a new one i have not seen. Interesting find. It does make sense though that it would make that sound. if the combustion gases are pushing passed the Coil seals and if the coil was shorting to ground. Cat should be ok. Glad you found the issue thanks for posting the cause.

kzak104

iTrader: (1)

almost sounds lke air escaping or something. vacuum leak?

hizzo3

Its a pet peeve when people don't post what happened.