[cxc511]

As the title says, I am experiencing an intermittent rattle / vibration sound coming from my engine (N52) at idle in my 2007 328i coupe with 58k miles. Some time ago, I experienced a similar sound and determined my air filter housing was not properly seated in the engine bay and easily fixed myself. Thinking it may be the same issue, I took a look under the hood but quickly determined it was not the cause.

While inspecting the engine, in addition to this noise, I noticed some oil residue on the front and side and decided to take a quick trip up to the dealer on my way to work. My SA was able to hear the sound and thought it could possibly be a drive belt pulley. He stated the oil was possibly a valve cover gasket issue. I was able to get the car in the following week and the source of the oil was actually the oil filter housing gasket which I had replaced. However, the tech did not hear the engine noise I mentioned while he had the car.

Any ideas as to what the cause of this sound could be? My car runs fine otherwise and the sound only seems to occur at idle. If one of the pulleys had a bad bearing or something, I would expect the issue to create noise constantly and increase with engine RPMs.

As an aside, my car had basically no issues under remaining factory warranty or CPO! It has been good to me, so I can't really complain if I have to put some money into it. However, my dealer's labor rate is $120 per hour and they mark up parts over list. The SA and tech are great guys, but I am definitely going to give an independent shop a try as I try to tackle this issue.

[SDemetris]

hmm it might have been some oil on the belt that made it slip, but once the oil wore off the sound went away.

[cxc511]

Originally Posted by SDemetris

hmm it might have been some oil on the belt that made it slip, but once the oil wore off the sound went away.

Thanks for your reply - that is what the tech said after he cleaned up some of the oil residue when the gasket was replaced. However I have been driving the car for a week and a half since and the issue still comes and goes.

[cxc511]

I have continued to have this engine rattle / vibration issue and have noticed the it only seems to occur when the car is cold. Given the frigid temps today, it sounded like a small semi at idle! Any ideas what could be the problem? The car continues to run fine otherwise.

[David0ff]

does the rattle maintain if you push the clutch in?
these bmw n52`s and all other equipped with the dual mass flywheel can be quite chatterer now and then

[cxc511]

Originally Posted by David0ff

does the rattle maintain if you push the clutch in?
these bmw n52`s and all other equipped with the dual mass flywheel can be quite chatterer now and then

It occurs whether the clutch is depressed or not. It seems only to occur at or near idle when the car is cold with RPMs below 1,000. If I step on the gas it will go away as the RPMs rise only to recur back at idle. When the car warms up the issue becomes less noticeable or goes away.

[Three_thirty_I]

Would you be able to take a video of this noise?

[Ferg]

I think I have the same problem. Mine sounds like when you crack the window and you get that buffeting sound. It is driving me crazy. I ordered some new motor mounts which I hope will fix it, we'll see if they ever come in the mail.

[cxc511]

Originally Posted by Three_thirty_I

Would you be able to take a video of this noise?

Hopefully this helps. I had filmed a couple of clips with the hood open following a cold start but the sound became the clearest after I closed the hood and the idle had fallen a bit. Hard to tell if it was coming from the front or the top of the engine when I have the hood open. I have read elsewhere the belt tensioner / idler pulley could be consistent with the sound occurring when the car is cold and then moderating somewhat?

[Three_thirty_I]

Hmm, will have to download this and listen to it on my sound system, but sort of reminds me of this vid:

Apparently the crank pulley bolt had failed and was causing a strange timing issue. The irregular idle "sound" seems similar, but not sure and not necessarily the same issue at all.

[left123]

Originally Posted by cxc511

As the title says, I am experiencing an intermittent rattle / vibration sound coming from my engine (N52) at idle in my 2007 328i coupe with 58k miles. Some time ago, I experienced a similar sound and determined my air filter housing was not properly seated in the engine bay and easily fixed myself. Thinking it may be the same issue, I took a look under the hood but quickly determined it was not the cause.

While inspecting the engine, in addition to this noise, I noticed some oil residue on the front and side and decided to take a quick trip up to the dealer on my way to work. My SA was able to hear the sound and thought it could possibly be a drive belt pulley. He stated the oil was possibly a valve cover gasket issue. I was able to get the car in the following week and the source of the oil was actually the oil filter housing gasket which I had replaced. However, the tech did not hear the engine noise I mentioned while he had the car.

Any ideas as to what the cause of this sound could be? My car runs fine otherwise and the sound only seems to occur at idle. If one of the pulleys had a bad bearing or something, I would expect the issue to create noise constantly and increase with engine RPMs.

As an aside, my car had basically no issues under remaining factory warranty or CPO! It has been good to me, so I can't really complain if I have to put some money into it. However, my dealer's labor rate is $120 per hour and they mark up parts over list. The SA and tech are great guys, but I am definitely going to give an independent shop a try as I try to tackle this issue.

OP, did you ever determine the cause of your rattle? I seem to be having the same symptoms and am interested in any headway you were able to make.

Thanks in advance.

[excel]

I had this issue. It turned out to be the alternator pulley.

[left123]

Originally Posted by excel

I had this issue. It turned out to be the alternator pulley.

Thanks Excel. Ill take a look at that now that you have given me something to try.

Did you do this yourself or take it in? Easy to fix? Just tighten it up or replace?

Thanks in advance.

[StealYourFace]

Does it go away when you put the clutch in? Could be a noisy throwout bearing.

[SDemetris]

I had a rattle that ended up being this

http://www.ecstuning.com/BMW-E90-328...st/OE/ES39969/

[excel]

Originally Posted by left123

Thanks Excel. Ill take a look at that now that you have given me something to try.

Did you do this yourself or take it in? Easy to fix? Just tighten it up or replace?

Thanks in advance.

It was a periodic groaning/rattling noise at idle just like this. First I changed the drive belt, no change, then the idler pulley, still nothing (though it did spin freely so it was time for replacement)

Then I bought an alternator pulley tool kit and a replacement pulley. It was strange - initially after changing it the sound was still there, and I went to bed ready to give up. But next morning it was gone and has not come back since.

I think the root cause may actually be something else and the pulleys wore to a point where the load on the crank was just enough to induce a weird harmonic, and changing the pulleys brought the load out of that range. Just a wild guess though, and I'm not worrying about it until it comes back.

[Stream]

Originally Posted by excel

Then I bought an alternator pulley tool kit and a replacement pulley.

Can you please post p/n or link on this kit.

[excel]

Originally Posted by Stream

Can you please post p/n or link on this kit.

I'm in Canada so not sure it will help, but it was this one:
http://www.princessauto.com/en/detai...et/A-p8466658e

It's similar to the one ECS sells, cheaper even:
http://www.ecstuning.com/Search/Site..._Tool/ES11415/

And similar ones on ebay as well:
http://www.ebay.ca/itm/13-Piece-Alte...item463c19e402

[BMWFan02864]

OP,

I have the exact same car with the same issue. Did you ever figure it out?

Thanks