engine noise at idle

[infurno]

When the car sits idle and the RPM hangs below 1k there is a bumping sound from the engine compartment. It started really small, and when I would press the clutch it went away... But now its got much much worse, and clutch no longer has any effect.

The best I can describe the sound is kind of like the sound from a table or a chair with 1 short leg. When you tip the table on the bad corner and it hits the floor. Making a bump noise.

When the RPM is over 1k there is no noise at all.

Its getting worse every week, and I can't figure it out.

Also, the noise is not always there.

[dauchande]

When the car sits idle and the RPM hangs below 1k there is a bumping sound from the engine compartment. It started really small, and when I would press the clutch it went away... But now its got much much worse, and clutch no longer has any effect.

The best I can describe the sound is kind of like the sound from a table or a chair with 1 short leg. When you tip the table on the bad corner and it hits the floor. Making a bump noise.

When the RPM is over 1k there is no noise at all.

Its getting worse every week, and I can't figure it out.

Also, the noise is not always there.
Sounds like a bearing, Isn't there a "thruster" bearing in the flywheel/clutch assembly somewhere, I don't know the name of it, but that's one possibility.

Mine's an automatic (for now), so I have no actual experience with this, sorry.

[Ross]

It is worse with the engine warm or cold?
If worse warm it could be a main bearing getting loose. Pushing the clutch moves the crank forward and could account for the difference in sound.
Main bearings aren't as obvious as a rod bearing that has gone away.

[infurno]

I heard it this morning when I first started the car. So its still there when cold. I was hoping to hear that it was an engine mount or something.

Where is this bearing, and how tough is it to get it?

[Ross]

After reading your OP more carefully with your observation that is'nt always present I doubt it's a main bearing.
Without actually hearing it it's pretty tough to guess.
A piston slap will be more pronounced on a cold engine and M20s/30s are famous for it with high miles. Bearing knocks are worse when warm.
V-belts can make some pretty scary sounds and can also come and go, might be worth checking belt tension and condition. If you wet the belts and the noise quits you've found it.

[Claude]

When the car sits idle and the RPM hangs below 1k there is a bumping sound from the engine compartment. It started really small, and when I would press the clutch it went away... But now its got much much worse, and clutch no longer has any effect.

The best I can describe the sound is kind of like the sound from a table or a chair with 1 short leg. When you tip the table on the bad corner and it hits the floor. Making a bump noise.

When the RPM is over 1k there is no noise at all.

Its getting worse every week, and I can't figure it out.

Also, the noise is not always there.

Does it sound like this: http://s34.photobucket.com/albums/d106/tarheelbimmer/535/?action=view&current=DSCN1580.flv

[infurno]

Its close.

Mine is slower for sure, less like tapping and more like knocking. Not a light knock but sounds like something really hitting.

It started as maybe 1 beat per second. When I press clutch it went away.

Now its up to maybe 4-5 beats a second. Clutch no longer makes it go away. If the RPM is over 1K, there is no noise.

[Claude]

Its close.

Mine is slower for sure, less like tapping and more like knocking. Not a light knock but sounds like something really hitting.

It started as maybe 1 beat per second. When I press clutch it went away.

Now its up to maybe 4-5 beats a second. Clutch no longer makes it go away. If the RPM is over 1K, there is no noise.

Mine does the kind of knocking noise (like a diesel) you heard on the link, and the cause of this is the dual mass flywheel something loosen on that mechanism over time that produce the rattle noise à idle speed i was said almost nothing to do (unless changing the flywheel) but beside the noise there is nothing to worry about. Mine is like that since i have it (near 100000 km).

[ThoreauHD]

Engine mount. Cheap parts, but a PITA to replace.