Help! Rattling noise on idle

[ChelseaBoy]

Hi guys,
After burning a massive hole in my pocket I am looking for some advice. I have an e30 chromie but it makes a rattling sound when idling. If you put the clutch down the noise goes away, if you rev it, the noise goes away. I have just replaced the gearbox as I thought that was causing the problem. Imagine my face when after having the gearbox replaced, the problem is still there. I still have to replace the suspension and get a full respray and sort out some rust spots and many dinks.

Can someone please help with trying to pinpoint what is causing the rattle? I am at end of my patience and am seriously considering selling it. I have spent more than 3k on this car already and I am never going to get that back. I have replaced the head, changed timing belt, replaced bushes, exhaust, wheels and lots of other work to my 325i black 2 door chromie but I am so cheesed off that just don't want anymore hassle.

[e30mtec]

get a freind to do the same while you look over the car..i had this for ages and found it to be a loose bolt on exhaust tip...

[Rav335uk]

Exhaust touching the body somewhere.

[e30mtec]

seriously its bound to be something you will beat yourself over!

[cee]

Where is the sound coming from?

[Dezzy]

Snapped gearbox exhaust bracket?

Edit

Or rotten gearbox exhaust bracket

[town325i]

Its non of these as i changed the gearbox last week and everything underneeth is fine and the gearbox is a good one.

[bss325i]

If it goes when the clutch is depressed then this is normal to an extent.

It is the layshaft in the gearbox chattering when in neutral and when you depress the clutch, drive to the gearbox input shaft is taken away.

[e30topless]

the box is worn,

as barry states it's the layshaft, what's the tick over reading on the rev counter ?

[bss325i]

what's the tick over reading on the rev counter ?

+1.

The lower the idel speed or the more uneven the idel will make it more prominent.

[pony]

If it goes when the clutch is depressed then this is normal to an extent.

It is the layshaft in the gearbox chattering when in neutral and when you depress the clutch, drive to the gearbox input shaft is taken away.

I have this problem with my E30 325iS.

Would a new gearbox cure this problem?

Would this layshaft "rattle" be a problem if i took the car DRIFTING or should i be putting a new gearbox in the car?

Makes the car sound awful when it is in staitionary and the engine is running. Makes it sound like it going to fall apart

[pony]

for the record mine idles at about 600 rpm i think..

[drewjak]

if youve got lumpy tickover it will sound very nasty, a friend of mine thought his crank had gone, once he sorted his tickover out by cleaning the butterfly in the throttle body so it would close properly the car ticked over perfect and the noise had gone, phew

[ChelseaBoy]

The car idles at around 800. Am sick of this nasty sound.

[ChelseaBoy]

So you guys reckon it's a layshaft?

[TheRealStig]

If the noise goes away when you press the clutch, souunds to me like it could well be the clutch release bearing

[cecotto479]

If it were the clutch release bearing, it'd be noisy when yo put your foot on the clutch. It's not spinning at any other time. It's the layshaft bearing. The reason that changing the gearbox didn't fix it is that every BMW manual gearbox from the 1980s makes this noise.

[ChelseaBoy]

If it were the clutch release bearing, it'd be noisy when yo put your foot on the clutch. It's not spinning at any other time. It's the layshaft bearing. The reason that changing the gearbox didn't fix it is that every BMW manual gearbox from the 1980s makes this noise.

So what's the solution? Is there no way to shut the car up? I have had manual E30s before, but not this noise....

[pony]

If it were the clutch release bearing, it'd be noisy when yo put your foot on the clutch. It's not spinning at any other time. It's the layshaft bearing. The reason that changing the gearbox didn't fix it is that every BMW manual gearbox from the 1980s makes this noise.

So what's the solution? Is there no way to shut the car up? I have had manual E30s before, but not this noise....

me as well..

[Felix79]

So you guys reckon it's a layshaft?

Barry is a BMW tech so I would take his word as gospal.

[ChelseaBoy]

So you guys reckon it's a layshaft?

Barry is a BMW tech so I would take his word as gospal.

Cheers for that...only which one is Barry?

[JoeDiese]

The only way I've read of to cure this is to buy a rebuilt transmission from Metric Mechanics. When rebuilding the transmission they use tapered layshaft bearings, which can absorb the lateral movement of the layshaft.

The lateral movement is what causes the original bearings to wear out...

[ChelseaBoy]

Spend More Money?

Just going to stick it on Ebay now......had enough.....just love the drive though, hate the noises.

[Felix79]

So you guys reckon it's a layshaft?

Barry is a BMW tech so I would take his word as gospal.

Cheers for that...only which one is Barry?

bss325i

[bss325i]

My 60000 mile 325i does it slightly when stopping the engine.

My old E36 328i did it all the time in neutral.

My old 53000 E46 330Ci did it when stopping the engine.

I recently replaced a 6 speed box in a 2004 330ci with a brand new gearbox due to a worn syncro and even the BRAND NEW box did it but again you could only hear when turning the engine off.

[davidt]

if youve got lumpy tickover it will sound very nasty, a friend of mine thought his crank had gone, once he sorted his tickover out by cleaning the butterfly in the throttle body so it would close properly the car ticked over perfect and the noise had gone, phew

definitely agree with this make sure the tappets are not too tight and the cooling system is in top order.

[e30mtec]

why sell it..swap me with my tech 2 kitted 318i moredoor..id love a cabby

[cecotto479]

If it were the clutch release bearing, it'd be noisy when yo put your foot on the clutch. It's not spinning at any other time. It's the layshaft bearing. The reason that changing the gearbox didn't fix it is that every BMW manual gearbox from the 1980s makes this noise.

So what's the solution? Is there no way to shut the car up? I have had manual E30s before, but not this noise....

A good gearbox rebuild. They pretty much do all make the noise to some extent or another. You may need to listen carefully and it can be more of a change in tone than a noise, but I can barely remember any manual BMW from this era that you couldn't hear the layshaft on. Maybe I've been unlucky dozens of times, but......

If it's really rattly and grumbly and it definitely goes away with the clutch depressed, a gearbox rebuild will be needed sooner rather than later. Is the sound *exactly* the same as with the old gearbox or is it a different level of the same sound?

[JoeDiese]

I recently replaced a 6 speed box in a 2004 330ci with a brand new gearbox due to a worn syncro and even the BRAND NEW box did it but again you could only hear when turning the engine off.

My e30 makes the same noise I think you're describing when I turn it off, had me worried it was the big end going bad for a while before I figured it was the transmission.

[HairyScreech]

if it sounds a bit like someone shaking a pack of tic tacs forget about it its the gear box, the car will have rotted away before the average drive kills the box.

[e30topless]

a noisy layshaft is nothing to worry about, it will probably rattle for another 60'000 miles and won't let you down,

if the tickover is too low, it will be noisy on any 325i !

[pony]

I am thinking of getting a new gearbox on mine though to get rid of the noise though i might have to take a deep breath beforehand..though it is only worth it if i intend to keep the car for a while

was thinking of a secondhand gearbox but for all i know it could have the same problem!

[ChelseaBoy]

Exactly, I did just have one put in by twon325i, and it had the same problem........

[skipunda]

Moved to tech help

[ChelseaBoy]

The sound is lower than the previous gearbox, but its still there. Not paying for yet more gearbox work, even if I have to seel it.

Its a 2 door coupe chormie with electric windows, sunroof and its black with leathers and perhaps I should just sell it.