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2002 STS, 2008 BLS 2.8t
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30 Posts
Discussion Starter #1
Hello! My N* has started making a sound and I can’t figure it out for the life of me... it’s kind of like a tapping/hollow sound, it will just happen anytime out of nowhere whether the engine is cold or warm. The sound gets faster as the rpms rise and seems to disappear at around 2000rpm. Here is a link to a YouTube video, the sound it makes in the beginning is exactly how mine sounds

https://youtu.be/hx9jmEnDIp4

If someone could please tell me what it is and how to cure it that would be awesome! Because it’s really driving me crazy!

Thanks in advanved.
 

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Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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70,751 Posts
Gonna take some educated diagnosis by a good mechanic.

Sounds like a piston slap, but that's usually cold only. The Northstar flexplate ("flywheel") has been known to crack at the crankshaft flange bolt circle - it will knock like that until the crack extends to total flexplate failure.

BUT - that knock in the clip is at 1/2 engine speed - most likely valve train - or a piston slap on its power stroke.

Get a mechanic's stethoscope and carefully locate the area of loudest sound - that's a start.
 

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Registered
2002 STS, 2008 BLS 2.8t
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30 Posts
Discussion Starter #3
I should’ve been more specific, the sound I’m getting from my engine is the sound from 0.10 to around 0.19 seconds of the video clip, the higher pitched sound. Not the deeper knocking sound that starts after. Well really hoping it’s not piston slap or the fly wheel. Got 90,000 miles on it at the moment, runs like a dream.
 

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Registered
2002 STS, 2008 BLS 2.8t
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30 Posts
Discussion Starter #4
To be honest I’m not too familiar with the piston slap noise. I’ve heard it can sound the same as the “cold carbon rap”? From what I know of piston slap is that it only usually is audible on a cold startup, the sound mine is making can happen on cold or warm startups, it can just appear out of no-where when the everything is fully warmed up while the engine is running. Yesterday morning it was -6 here in Sweden, no strange start-up sounds at all, got to work fully warmed up and heard the tapping sound?? It’s just so strange and intermittent.
 

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2000 Deville Base (SOLD)
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39 Posts
That video is of my car. I’m not sure what the sound is either. I’m not extremely concerned about it because the car runs ok, and I’ve had it at a couple of garages and they didn’t seem concerned. You are right about the sound being intermittent though. It’s strange. It does have piston slap when cold.
 
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