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Discussion Starter #1
Hey Guys,

This is a bit of a long shot but I figured I'd ask anyway. I did some poking around with the search function but, I didn't find anything that seems related.

When driving around town, if I let the car coast (step off the gas) below 3k RPM the engine makes a loud clacking noise. If I push on the clutch, the noise goes away, or if I give it gas, the noise goes away. It only comes on when the foot is off the gas. It sounds very similar to the VANOS (perhaps it is) noise at startup. Is my VANOS going bad? Any thoughts?

Thanks,

HBP
 

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how many miles on the car? The chain is known to stretch after 120k miles, and it only shows off throttle.
 

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Discussion Starter #4
Hmmm, this makes a lot of sense. I've 136k on the car.

Does this mean I need a new chain or will I just need a new tensioner? Is this something that requires my immediate attention or can I plan on getting it done within the next 2k miles? Thank you so much!
 

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how many miles on the car? The chain is known to stretch after 120k miles, and it only shows off throttle.
It's not clear to me that the chain DOES unload on coastdown from 3000 rpm. The crank is still having to drive the cams and the valves open and close under relatively low cylinder pressure conditions.

OP, can you post a sound clip?
 

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My car has a sound on deceleration as well but I think it's from the back of the car. Its much more obvious with the rear seat out ( i replaced the fuel pump and am driving it like a stock car lol ) If your sure it's from the engine bay it might be timing chain related. i would try to rule out smaller stuff first such as front end wheel bearings , brakes etc. or be sure its not sound from somewhere else. If it has the original chain tensioner I would replace that. It's very easy to do. Good luck.
 

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Discussion Starter #7
My car has a sound on deceleration as well but I think it's from the back of the car. Its much more obvious with the rear seat out ( i replaced the fuel pump and am driving it like a stock car lol ) If your sure it's from the engine bay it might be timing chain related. i would try to rule out smaller stuff first such as front end wheel bearings , brakes etc. or be sure its not sound from somewhere else. If it has the original chain tensioner I would replace that. It's very easy to do. Good luck.

Thanks. I'll try to get a sound/video clip recorded so that I can post it. Is youtube the best way to do this?
 

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Crank is still the driving force no matter if it is being driven by the wheels or the pistons. Not sure where people get the impression the chain unloads? That said, is there not a drop in oil pressure under decel? If there is and one had a weak tensioner for either the vanos or main there might be a momentary chain noise.
Sound clip would be nice but they are so hard to tell much from.

There are two chains worth inspecting and for the price of an oil pan gasket.... I would simply drop the lower pan and look for plastic pieces, at the same time you can have a look at the oil pump chain and it's tensioner.
If there is no plastic it is unlikely the timing chain is the offender, that is what the plastic is for.
I don't really remember for sure but I think that was one of the symptoms to look for when you had oil pump chain problems. Search user name VantaaM5 and keyword oil pump chain and or tensioner.
 

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Discussion Starter #9
...of course when I tried to record the sound this morning on my drive to work, there was no noise. I will try on my way home after work and see if I've better luck. It does this all the time and I was shocked that it wasn't making the noise today.
 

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Clutch release bearing?
I have a car with that problem now. It only really makes a noise when you have the clutch disengaged (released) and have load on the bearing. Kind of a rattly grating noise.

OP confirm it's coming from the engine. Maybe a driveshaft or CV issue if it's coming from further back?
 

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Discussion Starter #12
Just to clarify, you mean disengaged as in the clutch pedal is pressed correct? If so, the noise for me occurs only when the clutch is engaged (clutch pedal out).

I did do several recordings but the outcome was not great. I'm going to try and attach a file so let's see how this goes. Please check to zip file attached.

The noise can be heard (click/rattling noise) at the 30 and 40 second mark. Please excuse the really bad recording.
 

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Discussion Starter #13
Just to clarify, you mean disengaged as in the clutch pedal is pressed correct? If so, the noise for me occurs only when the clutch is engaged (clutch pedal out).

I did do several recordings but the outcome was not great. I'm going to try and attach a file so let's see how this goes. Please check to zip file attached.

The noise can be heard (click/rattling noise) at the 30 and 40 second mark. Please excuse the really bad recording.
Is my sound clip completely useless? (I've a strong suspicion that it is.)
 

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Discussion Starter #15 (Edited)
It is for me. I can't hear anything different at 30 or 40 secs.
I'll try and record again with a different method. The sound that you hear at 40 secs... starts around 38 second mark is the sound. Before that, you don't hear anything but wind noise but, the rattling/click type sound happens once the gas is let off.

Thanks for taking the time to listen and sorry that I've wasted your time!

EDIT: It almost sounds like some bearing noise the more I think about it.
 

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Save yourself the trouble you need a good quality mike near the noise. I heard something but it sounded like a tinkle. You know the sound so when you listen your brain associates it.
 

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OK, now I hear it between 38 and 40 secs. Kind of like a ticking noise. Is it definitely related to engine speed? It's always around 3000 rpm no matter what gear you are in? Because it sounds more drivetrain to me. Something that gets noisy when the drivetrain is reverse loaded. The centre support bearing is famous for making weird ticking/rubbing type noises.
 

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Discussion Starter #18
OK, now I hear it between 38 and 40 secs. Kind of like a ticking noise. Is it definitely related to engine speed? It's always around 3000 rpm no matter what gear you are in? Because it sounds more drivetrain to me. Something that gets noisy when the drivetrain is reverse loaded. The centre support bearing is famous for making weird ticking/rubbing type noises.
Yeah, it's the ticking nose. It always starts around 3k RPM and comes down. I think it can be the support bearing as the drive train is slowing down at certain rotational speeds. I assumed it was coming from the front/engine bay. I'm not certain it is related to the engine, I just had assumed so. I'll do a search on the center support bearing. You wouldn't happen to have a part number or anything, would you? Either way, thanks!
 

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If it's always around 3000 rpm no matter what gear, it's likely related to the engine. The driveshaft speed changes a lot at 3000 engine rpm depending on the gear.

Another possibility is the oil filter housing hitting hitting on the inner fender. That's a common problem. It makes a noise and can make an annoying vibration too. The engine torques in the mounts the opposite way when you are coasting and the rear wheels are driving the engine. This could be moving the filter housing closer to the fender, if I have got my directions tight.

Check the rubber mounts on the housing and see they are loose.
 
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