[Three_thirty_I]

Searched and found this older thread, but was related initially to the 335i engines - there were some posters with NA engines suffering from similar rattling noises. Linked the thread below here - Lately I've noticed a rattle when accelerating...

But, essentially, my '05 E90 330i manual has been making this rattling sound pretty much since I got the car, but it seems as if it is more noticeable these days. It does it at lower revs and under normal or heavier acceleration. My first thought in the beginning was that it might be the exhaust flap actuator when it opens, but then the frequency and time that I hear this rattle does not make sense, so must be something else.

Also, since I bought the car it has always suffered from the brief throttle hesitation when planting your foot, especially at slightly lower revs when wanting to quickly accelerate past a slower moving car.

Could this be both related and an issue with one or more of the coil packs? Vanos seals?

The car is still under motorplan (few months left), and I did mention the hesitation at the last service, but no change.

So basically I want to know what to tell them to check so that they can't play stupid and not find the problem which will then escalate later on and become mine!

So any suggestions or ideas would be much appreciated! Oh, it's the N52B30 engine that I have, so the earlier Valvetronic engine...

[Alpineweiss e90]

Check engine and trans mounts. Look at the heat shields for the exhaust too.

[Three_thirty_I]

Actually just read about rattles that can develop from the exhaust mountings apparently, or so. Will definitely have them check that. Ideally want anything and everything checked and fixed before the car goes out of motorplan.

Just to add, I only hear this rattle when accelerating at lower revs and speeds with the window open - does sound like it's coming from underneath the car rather than from the engine itself. Over the years I've learnt to live and make peace with noises provided they are normal and part of a particular function, therefore benign, so until I know what this is, it is going to bother me.

[Three_thirty_I]

Found this on another forum, relating to 530i also using the N52 engines:

Could this be a DISA valve issue?

Not sure which car you have-if its a 530, specifically the N52 engine and even the m54 engine--I have had, and many reports of it, are the DISA valves in the intake manifold that control which air path is open depending on which RPM band you are in--can come loose and rattle around while accerlating (since that is when they open) but when you stop accelerating they close and produce no rattle.

This took 5 times toa dealer to finally diagnosis.

It was not so much a "rattle" but a "whurring" kinda sound that was subtle but if you heard it then you could not forget it.

The check is to remove the intake manifold and inspect

THe thing is if this is missed and parts come loose inside the manifold-they get sucked into the engine and its good bye engine.

The only reason they found mine is I asked to have my spark plugs changed and they inspected the manifold as part of the service and found one of the Disa valves literally laying in the manifold completely broken off--if sucked in that would have been goodbye to the engine.

Otherwise lots of benign things cause rattling but if its only during acceleration--this is one of the fewer things that can do that. Search the web for DISA valve failure and do some reading

[RupertPupkin]

Clutch chatter. Normal.

[Three_thirty_I]

Originally Posted by jimmydever

Clutch chatter. Normal.

Ah, interesting you say that!!! I was wondering it could be this, but am glad that this came up. Reason being, one thing that I do have is the common gearbox input shaft rattle or for that matter it is most likely actually the clutch - or maybe more specifically the dual mass flywheel.

Assuming I make peace with the noise, is it likely to get worse, or lead to more significant problems rather than just being a tab annoying? I have come to realise that the less the agents fiddle the better, unless of course it is absolutely necessary!

To be clear, the engine seems to be free of the fairly common and well documented metal ticking sound that is stickied above, but when the clutch pedal is not depressed there is the distinct rattle from the clutch/flywheel, especially when parked next to a wall with the windows down.

Also, on odd occasions when starting the engine there is a similar chirp sound as the engine takes - was able to replicate this for the SA and was told that it is normal for the dual mass flywheel.

So with all said, leave well alone or rather let them replace the clutch and dual mass flywheel? I have read and seen people replace the dual mass with a single mass, but I am not keen on this because the reason for it is to dampen vibrations from the engine - heard somewhere that (not sure if this was specific to the E46 M54B30) there are massive vibrations at higher revs with the 3.0i engines.

[Three_thirty_I]

Found a vid on Youtube of the noise I hear when the clutch pedal is out and in neutral:

Found an interesting animation showing how the dual mass flywheel works, so pretty easy to see how noises and rattles can be generated...

[Three_thirty_I]

Just to revisit this thread that I created when these problems started, and clearly, up to date has not been solved!

I took this stupid car to a BMW dealership just after posting this thread with the idea of the dual mass flywheel being the cause of this rattle and took one of their techs for a test drive to demonstrate this. He immediately claims that I am driving too low in the revs and under load which to be honest was the biggest load of nonsense! Driving on a level surface or a moderate incline in 3rd gear from 1500 rpm with light throttle position is hardly unreasonable for an engine like this - even smaller four pot engines are fine with this! Anyway, so he insisted that it was NOT the DMF but a case of the engine pinging! Fine, being under motorplan I just wanted this sorted out.

They updated the software (fiddled and moved my manual seats), claimed to have tightened an exhaust bracket, but the problem persisted and remains to this day after numerous other attempts. A summary of things done since then:

Replaced all spark plugs, replaced both DISA flaps, replaced both temperature sensors, cleaned both Vanos Solenoids, ran a tank of fuel with an injector cleaner, cleaned the MAF, currently running a custom tuned software to increase fuel mixture (to curb pinging from maybe over lean mixture), changed oil and filter. Have had codes read and absolutely no errors found. I also tried the BMS PBX which just aggravated things.

I really don't know what more to do, and frankly, I have lost all interest in this car, and the money wasted trying to fix this!

Has anyone had similar symptoms and traced it to anything viable?

[Blixem]

Howzit Three_thirty_I,
I have the same problem with my 330i.

Mine seems to be under light throttle, or trailing throttle. Mine has been going on for a couple of years.
For some diagnosis, I unplugged the flap actuator in the boot/ trunk, and that stopped the noise. So I totally believe my sound is coming from the exhaust flap.

I have not spent time play with the flap or actuator to see if something is loose, or if it is an easy fix.

Another thought, check the junk yards for a crashed e90, and buy just that part if it turns out to be the culprit.

cheers
Mike
(Saffer living in Canada)

[Three_thirty_I]

Originally Posted by Blixem

Howzit Three_thirty_I,
I have the same problem with my 330i.

Mine seems to be under light throttle, or trailing throttle. Mine has been going on for a couple of years.
For some diagnosis, I unplugged the flap actuator in the boot/ trunk, and that stopped the noise. So I totally believe my sound is coming from the exhaust flap.

I have not spent time play with the flap or actuator to see if something is loose, or if it is an easy fix.

Another thought, check the junk yards for a crashed e90, and buy just that part if it turns out to be the culprit.

cheers
Mike
(Saffer living in Canada)

Hi Mike,

Thanks for your reply!

Hmm, was always wondering about the exhaust flap, but the noise is heard at various engine speeds, and in some cases higher loads where I would imagine the exhaust flap is open. Generally it is heard when the engine is under part load and even when still pretty cold, so it is very possible that it is this since I know that part of the function of this flap is to assist in the warm up cycle by staying closed - something about preventing too much of the warm exhaust gases from going out.

How do you (or where in the trunk) unplug the actuator? I always thought it was a simple case of disconnecting the pipe that goes to the actuator and then clamping with a cable-tie...

At the end of the day, if it turns out to be this actuator then I actually don't "mind" the noise since it is then not caused by an issue with combustion process (as in pinging), sort of like the often annoying brake wear sensor squeal - common noise but not a cause for concern.

Edit:

Okay, found a link showing how to do this: http://www.e90post.com/forums/showthread.php?t=80661

[Three_thirty_I]

We have been having lots of wet weather so only been able to properly test this today. Sadly the rattling noise persists, albeit maybe slightly less noticeable, but still very much there. Maybe the somewhat louder exhaust note is just able to mask it a bit better. Quite disappointed that this has not solved the problem, was really hoping that it was something as simple as this in the end, but clearly this damm car is not going to make it easy for me, ever! And logically, if this noise was related to a rattling cat then having the valve permanently open would increase, not decrease the noise (maybe not the right conclusion), surely?

So back to square one - on a plus side, do like the "bigger" exhaust note...

[polskatomek]

Originally Posted by Three_thirty_I

We have been having lots of wet weather so only been able to properly test this today. Sadly the rattling noise persists, albeit maybe slightly less noticeable, but still very much there. Maybe the somewhat louder exhaust note is just able to mask it a bit better. Quite disappointed that this has not solved the problem, was really hoping that it was something as simple as this in the end, but clearly this damm car is not going to make it easy for me, ever! And logically, if this noise was related to a rattling cat then having the valve permanently open would increase, not decrease the noise (maybe not the right conclusion), surely?

So back to square one - on a plus side, do like the "bigger" exhaust note...

Did you ever figure out what the rattle was? I have an E90 '05 build 330i also and experience a rattling from what sounds like the engine bay (intake manifold??) under acceleration when cold, but before I take it apart and/or dump money into buying a new DISA valve, want to explore what other people found with similar symptoms...

[White330]

I have the same problem with my 06 330. It seems as though the rattle is worse when the engine is cold for me. Kind of embarrassing how loud the rattle is when in low revs. Let me know if you find anything out. I've tried everything but change the DMF

[polskatomek]

Originally Posted by White330

I have the same problem with my 06 330. It seems as though the rattle is worse when the engine is cold for me. Kind of embarrassing how loud the rattle is when in low revs. Let me know if you find anything out. I've tried everything but change the DMF

Oh man... alright. One thing I was thinking is maybe when the engine and ambient temperature is cold the upper DISA valve is opening and closing (ie. "rattling" ), trying to accomplish normal operating temperature quicker... I dunno if that makes sense or not

[SDemetris]

This happened to me. It was the exhaust mount that comes from thw transmission. It got loose somehow and rattled when i accelerated .

[White330]

Originally Posted by polskatomek

Oh man... alright. One thing I was thinking is maybe when the engine and ambient temperature is cold the upper DISA valve is opening and closing (ie. "rattling" ), trying to accomplish normal operating temperature quicker... I dunno if that makes sense or not

Yeah that makes sense. Didn't really think about that... seems like its coming from under the car more is the only thing, but sound does travel in weird ways.

This happened to me. It was the exhaust mount that comes from the transmission. It got loose somehow and rattled when i accelerated .

This is what it sounds like it would be, but I had them checked months ago and they said they were fine.

[polskatomek]

Originally Posted by White330

Yeah that makes sense. Didn't really think about that... seems like its coming from under the car more is the only thing, but sound does travel in weird ways.

In all likelihood our rattles are coming from different places lol… Unless I throw a code I'm going to try to not let it bother me too much. As the adage goes: "worry less, drive more"

That being said, when I change my spark plugs in a short while I don't think it'll hurt to take a look at the DISA valve to make sure it's not pooched

[Clammy]

I had a rattling under light accel, and it turned out to be a loose O2 sensor. She threw a couple of codes that I'm not sure are related, but the shop I took her to cleared the codes, tightened the sensor, and the rattle is gone, and the codes haven't reappeared. It's been about a week since she was in the shop.

Cheers!

[CYL]

I have got similar issue too, mine is N52B25
Metallic rattling sound when accelerate, particularly between 1000-2500rpm, usually happens when I try to accelerate.
Took the car to 3 different workshops and tried to demonstrate the sound to them but neither of these visits was success.
However it happens quite often when I am driving it daily, just not showing up the noise each time when I showed to the mechanic.

Has anyone found out what might be the cause?
I am just worrying if there is anything inside the engine being wrong, such as pinging.
And the sound is getting louder and louder since it first happened a year ago...

[Three_thirty_I]

Replied to your PM. I am noticing more and more BMW's pinging, makes me wonder if our fuels are getting worse as time goes by.

[tc535i]

If it's clutch (actually flywheel throwout bearing) chatter, you'll hear it revving in neutral with left foot off, but putting the clutch pedal down will get rid of it.

[Three_thirty_I]

Originally Posted by tc535i

If it's clutch (actually flywheel throwout bearing) chatter, you'll hear it revving in neutral with left foot off, but putting the clutch pedal down will get rid of it.

Yep, that was years ago when I didn't know what the noise was and tried to see what members here thought it might be - the noise was suspected as being caused by a chattering dual mass flywheel, but when I too the car to the dealer they said it was not that, but instead indicated the engine was pinging. And this has been an ongoing problem with lots of money thrown at parts, labour, diagnostics, coding, etc.