[deeebo8452]

Hi I was hoping someone could help me on this.

I just got my BMW E92 320d 2007 Manual serviced and noticed a week or so after this slight what I would describe as a deeper than usual humming sound that comes from the engine which sets in as the car is between 1000-1500 rpm.

Any ideas? Could it be signs that the gearbox is on the way out or perhaps something else? Someone who just sits in the car would not notice it but because I have been driving it daily I can definitely notice the difference - also the accelerator pedal seems as though it has a bit of feedback when between those rpm's (normally as the car is decelerating from 1500 to 1000 rpm. Just to add the car has just hit 80,000 miles (which i have been told is whereabouts the gearbox is on its way out). If if is gearbox how much does this normally cost and roughly how much is labour?

Any of your thoughts would be appreciated

Fingers crossed its nothing serious

[waftingtony]

Hiya...
Fear not, after a service it sounds more familiarly like a loose acoustic engine cover (the plastic cover that sits on top of the engine), so it might not have been tightened down properly (allen key bolts). Further to this, it could be the airbox (which is plastic and screwed down) that hasn't been tightened up. The resonance of diesel engines will always pass these vibrating plastics back into the cabin if not screwed back together. Had this happen on all my BMW diesels by either myself forgetting to tighten a screw, or my Indy.
Have a look at this first before thinking worse things..... if its gearbox, you'll REALLY know about it and it tends to rumble like thunder.

[deeebo8452]

Originally Posted by waftingtony

Hiya...
Fear not, after a service it sounds more familiarly like a loose acoustic engine cover (the plastic cover that sits on top of the engine), so it might not have been tightened down properly (allen key bolts). Further to this, it could be the airbox (which is plastic and screwed down) that hasn't been tightened up. The resonance of diesel engines will always pass these vibrating plastics back into the cabin if not screwed back together. Had this happen on all my BMW diesels by either myself forgetting to tighten a screw, or my Indy.
Have a look at this first before thinking worse things..... if its gearbox, you'll REALLY know about it and it tends to rumble like thunder.

Thanks for your reply mate. Oh how I hope its just that. I know the engine cover your referring to but where is this airbox? Im pretty sure the engine cover is just meant to clip on as opposed to any allen key bolts (correct me if i am wrong). Nonetheless I will check this once I get home - but is there a reason why I only hear this humming noise between 1000-1500 rpm, it is always between those revs for some reason! Although its by no means rumbling like thunder but I thought perhaps it might be early signs - lets hope not!

[Icekube]

who ever told you that the gearbox is on its way out at around 80k needs a slap....

[waftingtony]

With a car as young as that, its very unlikely to be gearbox unless its been given serious harsh treatment. The reason at that rpm, is simply due to the nature of the diesels on tickover. They sit on rubber engine mounts that, over time, slightly wear down. So there becomes a little bit of play with the engine movement on tickover. Thus plastic parts stuck on top i.e airbox flute at the front & the acoustic cover, can rattle around because of physics.. resonance may occur as the engine increases revs but you won't hear it as much. Just like sitting on the back of a bus above the engine, you feel more vibration on tickover. Don't worry so much and just check these first. Hope thsi is a corerct diagnosis anyway :-)

[deeebo8452]

Hi well I did get the engine plastic cover double checked and it seemed that it was a little loose and the guy switched those rubber things around and it seems to hold a lot better. However I still experience what I would describe as a "deep humming noise" from the engine between 1500-2000 rpm, usually in first and second gears. Once I get above 2000rpm the noise goes away. But I think this noise has got louder over the couple months. As mentioned its a BMW 320d e92 coupe2007 at around 82,000 miles.

After googling I have seen suggestions that it could potentially be the gearbox or camshaft. Any ideas or advice would be welcome. To be honest its not like the car is sluggish or anything but I want to know whether there is an underlying issue I should be concerned about as I wouldnt want it to pack up all of a suddent

Thanks in advance guys

[Will335d]

Originally Posted by deeebo8452

Hi well I did get the engine plastic cover double checked and it seemed that it was a little loose and the guy switched those rubber things around and it seems to hold a lot better. However I still experience what I would describe as a "deep humming noise" from the engine between 1500-2000 rpm, usually in first and second gears. Once I get above 2000rpm the noise goes away. But I think this noise has got louder over the couple months. As mentioned its a BMW 320d e92 coupe2007 at around 82,000 miles.

After googling I have seen suggestions that it could potentially be the gearbox or camshaft. Any ideas or advice would be welcome. To be honest its not like the car is sluggish or anything but I want to know whether there is an underlying issue I should be concerned about as I wouldnt want it to pack up all of a suddent

Thanks in advance guys

Hi I had this happen on a 320d low mileage bought from BMW auc that had just been services before sale, the airbox bolts were barely in and the rubber mount wasn't on properly took 2 mins just have a good look about

[deeebo8452]

I know I am going to sound like a right pleb but where exactly is the airbox, is that the housing for the air filter? And is the rubber mount part of the same "airbox". Im cringing asking these stupid questions lol

Originally Posted by Will335d

Hi I had this happen on a 320d low mileage bought from BMW auc that had just been services before sale, the airbox bolts were barely in and the rubber mount wasn't on properly took 2 mins just have a good look about

[Red_Bean_Bun]

Yes, it's the housing for the air filter .....

Originally Posted by deeebo8452

I know I am going to sound like a right pleb but where exactly is the airbox, is that the housing for the air filter? And is the rubber mount part of the same "airbox". Im cringing asking these stupid questions lol

[deeebo8452]

You were right thanks!

Basically it wasnt the air box itself rather there is a kind of plastic flow pipe that goes from the air filter to another box at the front middle section in front on the engine, there was some slack where these two joins. As a quick fix I just got a little bit of cardboard and wedged it in between to tighten the slack. Such a bog job I know but did the trick

I have also noticed that the performance and general smoothness of drive has improved since. Perhaps air was escaping or something I am not sure anyways thanks for all your advice and replies on the matter. Was getting worried it might have been something serious

Originally Posted by Will335d

Hi I had this happen on a 320d low mileage bought from BMW auc that had just been services before sale, the airbox bolts were barely in and the rubber mount wasn't on properly took 2 mins just have a good look about