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Random squeaky noise

Hey I’m new, see some post from the forum on Google figured if I asked a question maybe I cld get some help. My bf has an 09 g8 gt and a few days ago it started making this squealing noise (same noise u hear with bad pulley or belt issue) so he removed the belts and started…we still hear the squeaky noise. The noise is a consistent sounds that starts immediately at idle and is constant while driving. He is a little frustrated with the car so I figured I wld ask and maybe get pointed in the right direction. I don’t know a whole lot about cars so please do laugh me out of the forum lol​:joy::joy:

Does it change pitch or rate as engine speed increases?

Can you post a sound clip?

The sound doesn’t change its the same constant noise, and the noise just speeds up with the speed increase but it doesn’t get louder. I can post a clip on my break.

I’m not able to upload the clip it keeps saying the file wont work and I have tried converting the file name also no luck. I’ll have to keep trying.

Finally got the video

That sounds like an idler pulley to me. If he removed ALL the belts, started it, and the noise remains, it can only be INside the engine - and that’s not good.

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if it were engine related wldnt there be a misfire? Or does the harmonic balancer pulley go around the idler pulley?

No misfire. There is no ignition timing controlled by belts on the front of the engine. The belt that runs over the balancer does run over the idler.

If it is a bearing inside an idler pulley there is no connection to anything that makes the engine run. You can start and run the engine for a minute with all the belts off. The water pump won’t be turning so dont run it long. With belts off you can turn everything but the balancer by hand to find any bearing roughness. That roughness causes a squeak.

Does it occur both idling in the driveway and while driving down the road? If only when driving down the road, does it sound the same when coasting vs in gear? Any change to the sound when the brake pedal is applied? When you say the noise speeds up the faster you go, do you mean it changes to a higher pitch? From an oooooooh to eeeeeee sound the fast you go? Is there any change to the sound when using different gears, or if a manual when the clutch pedal is pushed in?

One thing you could try, get a length of old garden hose and use it as a stethoscope to better isolate where in the engine compartment the sound is coming from.

Other possibilities

  • Parts that vibrate can sort of sound like a squeal. The cat heat shield is one of the most common causes of vibration sounds.

  • Vacuum leaks can make a squealing sound. I’ve had that happen before from a vacuum leak at the valve cover gasket. Not a soft squeal, really loud, but only happened when the engine was warm. Use the garden hose, maybe it will point to a vacuum leak somewhere. That kind of sound will tend to diminish if you temporarily bump the throttle, and be loudest with your foot off the gas. PCV valves can sometimes make a vacuum sourced squealing sound.

The car is an automatic but the car sounds the through all gears. And I stood beside to hood to see if the sound changed when floored it and it remained the same as in the video just a lot faster.

Not sure if it means anything, but last week the car was throwing a #2 misfire code turns out the problem was a the lifter (I’m sorry but this is the only way I can explain it) the lifter in cylinder 2 has a roller end on it and the roller piece was pushed in and the spark plug wasn’t firing. In my mind I think maybe there is a problem with the cam that caused that lifter to fail and now maybe it’s making the squeaky noise because it’s just doing the same thing again??? But tomorrow we will have all day and we will try the garden hose. Thanks for all the suggestions.

A defective roller on a lifter might prevent its valve from opening fully, which could cause a misfire. But it wouldn’t normally cause the spark plug not to fire. A normal firing involves air + gasoline + compression + spark. If any of those are missing you’ll get a misfire. If the valve doesn’t open fully you’ll not get the air+ gasoline; if the valve doesn’t close fully you won’t get the compression. I’d guess that a faulty lifter roller could indeed cause a squealing sound if it was somehow grinding against the camshaft lobe as it came around. Does the sound have a sort of pulsation to it? If so that could be the cam lobe coming round and round and hitting against the defective lifter each time. I think you may be onto something there. Tech difficulties prevent me from listening to your vdo unfortunately.

A week after replacing the camshaft and lifters? Or just one new lifter on a damaged camshaft? Time to return to the scene of the crime, what is the opinion of the person who performed the repair?

There may be significant damage now, the engine may need to be disassembled to clean out the metal debris and replace the damaged parts.

Order new cam, lifters, ect. Once we start taking everything apart I’ll post pics.

It will be interesting to see what problem you find there OP.