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Sound Diagnosis [With sound file!] Hollow clunking on idle, low RPM Topic is solved

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ToriWhite
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Sound Diagnosis [With sound file!] Hollow clunking on idle, low RPM

Post by ToriWhite » Fri Mar 16, 2018 11:43 pm

I've got some trouble with a hollow clunking sound, it seems to make itself known when I'm either easing off or pushing on the accelerator, almost always when reversing, always when turning the car off and sometimes when idling (regardless of clutch being in or out, breaks on or off, but eases off if I rev it a hair past 1k rpm in neutral)

I know it is NOT from my struts, I've just replaced them and my spring seat / bearing YESTERDAY (Still sore!) .. I'm hoping this is a clutch problem since I have the parts and will be replacing that soon.. fingers crossed..

I hope someone with more experienced ears can tell me what this sound is! What you're hearing in the file is the idle of the car just before turning it off, and then the sound of me turning it off, I ask the audience to please note the unusual clunking that persists throughout

( I Couldn't link to youtube, they won't let me upload just a sound file .. and I didn't want to host anything for y'all to download, so I made a video on Biteable using stock film, please listen HERE)


EDIT:

I fixed it! We were digging around under the car for another project (replacing the clutch, had to pull the WHOLE thing out!) we found 3(!) Separate hose leaks from various air systems .. not minor pinholes, but rubber elbows that were open, and crumbled in your hand.. Anyways- we replaced those, and the noise is gone! voila!

I put all those rubber elbows in from a kit from ICP when I first bought the car 3 years ago.. let this be a lesson to you all- Do NOT cheap out on your rubber hose components! They're already so cheap, why not put the extra $5-20 to get the highest quality ones? Trust me, it's worth it!
Last edited by ToriWhite on Mon Mar 19, 2018 11:21 pm, edited 1 time in total.

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Re: Sound Diagnosis [With sound file!] Hollow clunking on idle, low RPM

Post by scot850 » Fri Mar 16, 2018 11:51 pm

Not sure what your link is taking me to, but can't hear anything.

Neil.
2000 V70 R - still being an endless PITA
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Re: Sound Diagnosis [With sound file!] Hollow clunking on idle, low RPM

Post by ToriWhite » Fri Mar 16, 2018 11:56 pm

scot850 wrote:
Fri Mar 16, 2018 11:51 pm
Not sure what your link is taking me to, but can't hear anything.

Neil.
Sorry, I didn't have any professional sound equipment to capture it, so you gotta kinda strain your ears past the shuffling I make handling the keys.. It helps turning it up, the recording is pretty quiet

The rhythmic clunking isn't the normal engine sound, imagine that louder with a normal engine purr underneath it

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Re: Sound Diagnosis [With sound file!] Hollow clunking on idle, low RPM

Post by wizechatmgr » Sat Mar 17, 2018 12:35 am

Would suggest trying to capture that from the engine compartment with the hood open. Obviously you'll need someone else to start it.

Sounds almost like she's not firing on all cylinders.

If all else fails, toss the audio file on something like google drive and I'll see what I can do with it Monday morning.
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In order to learn how to fix something, you must first learn how to break it.
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Re: Sound Diagnosis [With sound file!] Hollow clunking on idle, low RPM

Post by ToriWhite » Sat Mar 17, 2018 12:56 am

wizechatmgr wrote:
Sat Mar 17, 2018 12:35 am

Sounds almost like she's not firing on all cylinders.
!!!

I'll get a better recording tomorrow.. yikes! Is that a death sentence for my engine block? On par with blown headgasket?

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Re: Sound Diagnosis [With sound file!] Hollow clunking on idle, low RPM

Post by wizechatmgr » Sat Mar 17, 2018 1:35 am

Nah, could be a number of simple reasons. Anything from spark plugs that need to be replaced to bad wires, fuel injection problem... I wouldn't immediately assume anything that's a total death sentence at this point.
Wisdom requires knowledge as a prerequisite, but knowledge can be developed due to a lack of wisdom.
In order to learn how to fix something, you must first learn how to break it.
1999 V70 XC AWD - ~187k miles

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Re: Sound Diagnosis [With sound file!] Hollow clunking on idle, low RPM

Post by ToriWhite » Sat Mar 17, 2018 11:29 am

I don't have any friends to help me :( , and it wasn't rattling in idle (only in reverse, this time) so I couldn't run out and open the hood.

I've got audio of engine opening up normally with me turning it on ; and then when I put it in reverse and reverse it (I'm navigating out of a parking lot) the rattling starts, its a pretty good example of the distinction between what it normally should sound like (the beginning) and then when the culprit sound appears!

Try listening with high volume , its kind of quiet!

https://biteable.com/watch/rec-2-1801088

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Re: Sound Diagnosis [With sound file!] Hollow clunking on idle, low RPM

Post by ZionXIX » Sat Mar 17, 2018 2:27 pm

You could set your phone to record and secure it in the engine bay some how or tie some wire around it and suspend it form the hood (lots of ways to rig this) and then go start the car, count to about 20 and then go stop the recording.

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Re: Sound Diagnosis [With sound file!] Hollow clunking on idle, low RPM

Post by wizechatmgr » Sat Mar 17, 2018 5:09 pm

The problem is the audio signal quality is so low that even when fully cranked it isn't sufficient.

Kind of like putting your head in a water jug and then submerging and then trying to figure out the sounds on the surface of the water.

ZionXIX's idea is great. My suggestion would be to tape it to the top of the air box with the mic end of the phone pointing toward the engine.
Wisdom requires knowledge as a prerequisite, but knowledge can be developed due to a lack of wisdom.
In order to learn how to fix something, you must first learn how to break it.
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Re: Sound Diagnosis [With sound file!] Hollow clunking on idle, low RPM  Topic is solved

Post by callahanoffroad » Sun Mar 18, 2018 3:08 pm

Yeah, I would second that it sounds like it's not firing on all cylinders. Pull the spark plugs and see if any of them are wet or smell like gas. That's probably where I would start. That and it sounds like you have an exhaust leak.

How's the idle? Is it rough?
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