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Hi. I'm getting a strange, not very loud rattling sound.

 

Car is an 08 E61 535d lci. 140,000miles ish..

 

It happens in 3rd gear (in manual mode) and in drive if its in the same gear, between 30 and 40mph, accelerating relatively hard from 1,500 to over 2000 rpm. 

I think it's coming from lhs of engine bay, but others say it's from everywhere (front, back, centre etc-not much help). 

Sounds like a mounting maybe, but could be prop bearings (csb) or rubbers (guibo thing) etc, but it's ok at other speeds and gears.

Also noticed earlier that it's not quite as smooth when starting off or low speeds. 

 

Has anyone had similar symptoms or noises? Are these indicative of anything specific.

 

Not had a chance to have a proper look yet.

 

I did open the bonbet and stick it in drive/reverse to see the movement, of which there was some but I don't think the mounting has truly 'gone'. 

 

I've recorded it but it's not very easy to hear. I'll need to edit it a bit, I'll try to upload it later, if I can get a sound file to work!

 

Thanks

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If it is a rattling then hopefully it is nothing too serious as opposed to a deep rumble which always worries me more - just my opinion. I've not had anything like that when driving at 30-40mph but mine did rattle if I was in traffic at <10mph or if I was stationary with the engine running. It was the heat shield on the exhaust which I fixed with a TIG welder. I can't recall hearing it at speed but perhaps my hearing isn't great!

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Thanks for your input. I don't think it's a heat shield, it's not as tinny and it's only obvious under these conditions. Same speed range in a different gear doesnt produce it nor the same rev rangein a different gear, but it does vary with the throttle position furing the time it makes the noise.

 

Here is the sound file. It's not completely clear, but if you get it loud enough you can hear two instances of this rattling sound, they are at about 12seconds and 23seconds.

 

Voice 042_sd.m4a

 

They certainly weren't there before, I think they've crept up recently.

 

I checked the lh engine mounting last night, the cop central nut was not tight, I've since nipped it up but no difference in the sound :(

 

I think it's there at higher revs, but engine/road noise masks it. 

I'm thinking the torque/reaction on the engine or other components is allowing something to easily move around.  In lower gears the engine might be moving too much and in higher gears there's not enough movement. 

 

I'll pop in to see my brother to listen to his over the weekend too, seeing his is a near identical car! I'll also hopefully get a peek underneath to check various bits and bobs.

 

Thanks.

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Just changed the ns(lh) engine mounting. The top half of the original one was rattling around, pretty loose. Hoping this was the cause of the sound.

Will be changing the os mount tomorrow and probably the gearbox mount as well, for completeness' sake. 

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Update:

Just changed the drivers side mounting, so both have now been changed.

Old one wasn't bad, it wasn't rattling around like the lh mounting but loads of bits of 'stuff' fell out of it when I held it upside down. 

Infuriatingly the rattle/noise remains, but is a bit better (I think!).

Gearbox mount shall be next, already ordered. 

Failing that, I'll be digging deeper and going after the propshaft.  

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