[ft1330]

My new 2014 335i has developed a rattle soon after I picked it up. It manifests itself under moderate load from 10-40 mph between 1,000-2,500 rpm mark. I think it's coming from where the dash meet the windshield. It's diffuse from left to right along the entire windshield I believe. I tried pressing on everything on the dash while driving (HUD, center dash speaker, vent trim piece between dash and windshield...) to no avail. It might be coming from the engine bay. Looking under the hood I noticed a flimsy piece of plastic cover that rests on the windshield and is held down by some fasteners, maybe plastic clips or plastic screws. I think it's called the windshield cowl. it doesn't look sturdy at all or held down very firmly. I can produce a noise when I tap on it with my finger, it clicks on the windshield... Maybe at higher frequency due to engine vibration this piece of trim rattles against the windshield? This rattles somehow does sound like it involves the windshield.

Not sure what to make of it. Has anyone heard this before? Here is a video below. I recorded it when the noise was rather extreme yesterday night, tonight the noise was not as bad but definitely loud enough to be obvious. Sometimes it goes away entirely.

I'm planning on taking it to the dealer but i wanted to get community input first to give a few pointers to the tech.

Thanks for your help.

UPDATE: BMW has finally recognized and fixed this issue for all F30 335i cars out there! They released a bulletin describing the fix procedure in detail for your dealership. You need to bring this bulletin number to your dealership and they'll take it from there: SIB 64 01 14. The issue is with a large AC hose next to the engine, which, under engine load, vibrates, and transmits the vibration to the cabin through the firewall. The fix is to attach a specially developed weight to the hose in order to stabilize it and prevent the vibrations. I just got my car back from the dealership after applying this fix and the rattle is GONE See more info about the fix here: http://www.f30post.com/forums/showthread.php?t=949816

[TonyS]

I have a very similar noise, although mine is nowhere near as loud. Car is an August 2012 F30 335i. It started when the car was about 8 months old, and like yours, varies in loudness and sometimes goes away completely.

It's one of those noises that you just can't pinpoint - I've had several people sit in the front & back, and wherever you sit it seems to be at the other end of the car.

I got one of the technicians at the dealers to come out with me and he could hear it, so it went into the dealers last week and they tightened up/packed out some part of the floor pan. Needless to say, the noise is still there, so I'm going to have to book it back in again.

I shall be very interested in seeing what your dealer says. Make sure that you get someone to come out with you and confirm that they can hear it, otherwise you're likely to get the "no fault found" response.

[ft1330]

Will update as I progress in fixing this. It WILL be fixed trust me. I will not let them sweep this under the rug. Obviously the video will get their attention.

Now I very much doubt it's coming from the floor pan. It really sounds like something knocking at the windshield, it's hard to pinpoint where exactly, but definitely not the floor pan as the noise is about level with my head towards the front. And the rattling is somewhat akin to something knocking on the windshield. You know how the windshield resonates differently than metal or plastic... It's sort of like a windshield resonance.

From what I can tell there are only 2 things in the dashboard area that are likely to touch the windshield. The dashboard itself, on the inside. And on the outside the windshield cowl. At this time this is my prime suspect. Open your hood and go check this piece (see my pic below). It's so flimsy it's ridiculous.

My 2005 Hyundai is solid in this area. My 2013 Hyundai is solid in there too. My 2014 BMW? It's soft, pliable, and if I hit it lightly with my finger towards the center it knocks the windshield.... I will bring this to the attention of the tech.

I've looked it up online and I found an Infiniti G37 thread where people had to add foam under this piece where it meets the windshield. Look up "windshield cowl rattle"...

[TonyS]

I've just checked, and yes, that cowl is pretty flimsy. Mine rattles too if I tap it, and if I lift it slightly up and down it knocks quite audibly on what's underneath. Whether that's actually the noise I can here I'm not sure, but I'm going to pack something underneath it and see what happens. I'll report back.

[ft1330]

Nice, OK let me know what you find out. I'm going to try stuffing some cardboard or some foam in there if I can pry it up wide enough.

Best test is if you're brave enough to take out the wipers and then the cowl as well as the 2 triangular covers that are connected to the cowl. Then you drive a couple of days without this (hopefully it doesn't rain).

I'm not 100% sure it's coming from there either but it's my best guess at this point.

Eventually when I take it to the dealership I'll have an informed complain to make. Hopefully they won't have to take the whole car apart if I point them in the right direction.

[TonyS]

Originally Posted by ft1330

Nice, OK let me know what you find out. I'm going to try stuffing some cardboard or some foam in there if I can pry it up wide enough.

Which is exactly what I've just done about 5 minutes ago. It's tricky finding where you can pack underneath it as most of it seems to be just a huge space underneath, but there are a couple of places near the sides. I'll see if it makes any difference.

[Philipangoo]

sounds like vibration more then a rattle. You should definitely take it to the dealer i mean it doesn't sound like a noise the engine is making but perhaps something that's mounted on it or close.

[yemenmocha]

Mine does it too, but it is variable and unpredictable. On some drives I can't hear it when trying to make it happen - same RPM range and everything.

[ft1330]

Alright I installed the cardboard pieces under each and every clip of the cowl. I wedge a credit card under the seal and then wedge a cardboard piece under the credit card and remove the credit card.

The clips are definitely loose and the cardboard tightened them up real good. If that turns out to be the problem BMW ought to use tighter clips to keep the cowl firmly clamped down.

I'll report back but it may take a while since my rattle is very unpredictable as well. I haven't had it today. I'll drive around a bit and will keep you updated.

[ft1330]

Update on the windshield cowl. The fix didn't work... I got the same rattles basically even though the cowl wasn't moving around at all. It was pretty snug. I guess it's back to page 1.

Do any of you with the rattles have the center dash speaker? The HUD? The tiny satellite HK speakers in the A pillar? I'm sincerely hoping it's not from deep in the dash in order to avoid a complete dash-stripping by the dealership...

[TonyS]

Originally Posted by ft1330

Update on the windshield cowl. The fix didn't work... I got the same rattles basically even though the cowl wasn't moving around at all. It was pretty snug. I guess it's back to page 1.

Do any of you with the rattles have the center dash speaker? The HUD? The tiny satellite HK speakers in the A pillar? I'm sincerely hoping it's not from deep in the dash in order to avoid a complete dash-stripping by the dealership...

Oh well, at least that's one suspect eliminated. I don't have the center speaker, HUD, or speakers in the A pillars.

[Want the thrill]

Read page 3 of this thread over on the second generation X3 board:

http://x3.xbimmers.com/forums/showth...+rattle&page=3

3Bimmer posted a fix that worked for me. Took it to the dealer and showed them this fix (they had tried to fix it previously and failed). Don't know if your 3 series has the same set up as the X3, but I thought it was worth mentioning.

[ft1330]

Originally Posted by Want the thrill

Read page 3 of this thread over on the second generation X3 board:

http://x3.xbimmers.com/forums/showth...+rattle&page=3

3Bimmer posted a fix that worked for me. Took it to the dealer and showed them this fix (they had tried to fix it previously and failed). Don't know if your 3 series has the same set up as the X3, but I thought it was worth mentioning.

Thanks for pointing us to that thread. The 3 series cowling assembly looks like the X3 (post #64 in your thread). So far I was focusing on the cowl piece directly under the wipers but from the X3 thread it looks like it's another part. If my understanding of the X3 problem is correct, the triangular plastic part that has the wear marks, is banging on the strut brace?

I'll try something easy at first, not sure I want to start removing a bunch of parts but I'll try stuffing some cardboard here and there for now...

[Want the thrill]

Originally Posted by ft1330

Thanks for pointing us to that thread. The 3 series cowling assembly looks like the X3 (post #64 in your thread). So far I was focusing on the cowl piece directly under the wipers but from the X3 thread it looks like it's another part. If my understanding of the X3 problem is correct, the triangular plastic part that has the wear marks, is banging on the strut brace?

I'll try something easy at first, not sure I want to start removing a bunch of parts but I'll try stuffing some cardboard here and there for now...

Correct. I printed the thread and took it to the dealer and they followed the procedure and the noise is now gone. It was driving me insane. Hopefully this will be the answer to your noise problem as well.

[ft1330]

Alright guys some news.

I checked out Want the thrill's thread and tried to apply the X3 fix to the F30. The parts are a little different but the concept is the same. You have rain covers on either side of the engine protecting some electronic modules. Those covers have tabs that stick out and contact the strut brace. If you tap on those covers you will hear the tabs hit the brace. The brace is not only connecting the struts together but it's also bolted to a part of the frame that is in the center of the car right under the windshield. I can see how the noise might propagate to the windshield area through this connection to the frame. It seems extreme but why not...

So I took out the big engine rubber seal, and I could then take out the 2 plastic covers. It's pretty easy actually, just a few plastic clips. I wanted to take out the cowl itself but I would have had to remove the wiper arms first so I didn't. I just stuffed some cardboard/foam under the cowl tabs that are contacting the car frame.

Went for 2 test drives. I didn't hear the rattle! Now the rattle is somewhat intermittent and shows up when it feels like, so it could have been a quiet moment. I decided to keep the rain covers and the rubber seal out for a few days and I'll report back... It looks like the rain will still be channeled out even without the rain covers so I should be fine. Looks like the covers are just for when you hose down the car or something.

Thanks again Want the thrill for your suggestion and keeping fingers crossed...

[snowghost]

Originally Posted by ft1330

Alright guys some news.

I checked out Want the thrill's thread and tried to apply the X3 fix to the F30. The parts are a little different but the concept is the same. You have rain covers on either side of the engine protecting some electronic modules. Those covers have tabs that stick out and contact the strut brace. If you tap on those covers you will hear the tabs hit the brace. The brace is not only connecting the struts together but it's also bolted to a part of the frame that is in the center of the car right under the windshield. I can see how the noise might propagate to the windshield area through this connection to the frame. It seems extreme but why not...

So I took out the big engine rubber seal, and I could then take out the 2 plastic covers. It's pretty easy actually, just a few plastic clips. I wanted to take out the cowl itself but I would have had to remove the wiper arms first so I didn't. I just stuffed some cardboard/foam under the cowl tabs that are contacting the car frame.

Went for 2 test drives. I didn't hear the rattle! Now the rattle is somewhat intermittent and shows up when it feels like, so it could have been a quiet moment. I decided to keep the rain covers and the rubber seal out for a few days and I'll report back... It looks like the rain will still be channeled out even without the rain covers so I should be fine. Looks like the covers are just for when you hose down the car or something.

Thanks again Want the thrill for your suggestion and keeping fingers crossed...

Wow.

[TonyS]

Well, I spent some time dismantling the covers and carefully putting padded strips under the areas where they were knocking. After taking the car for a drive, the noise is exactly the same, so my noise at least is definitely not coming from this area.

Bummer.

Next stop, phone the dealer to book it in again.

[ft1330]

Originally Posted by TonyS

Well, I spent some time dismantling the covers and carefully putting padded strips under the areas where they were knocking. After taking the car for a drive, the noise is exactly the same, so my noise at least is definitely not coming from this area.

Bummer.

Next stop, phone the dealer to book it in again.

That sucks. Have you tried driving without the covers at all? I don't have a 100% guarantee that the problem is cured in mine. I'm driving without the covers for a few days to make sure... But my 2 test drives yesterday after taking the covers out and my drive to work this morning were quiet... I'll go for another test drive now.

[TonyS]

Originally Posted by ft1330

That sucks. Have you tried driving without the covers at all? I don't have a 100% guarantee that the problem is cured in mine. I'm driving without the covers for a few days to make sure... But my 2 test drives yesterday after taking the covers out and my drive to work this morning were quiet... I'll go for another test drive now.

No, not tried without the covers, but I did put felt packing in several places so that the covers make no noise at all now when you tap or knock them. Will give it a try though.

[ft1330]

Originally Posted by TonyS

No, not tried without the covers, but I did put felt packing in several places so that the covers make no noise at all now when you tap or knock them. Will give it a try though.

It looks to be safe to drive without them. If you look at how the rain gets channeled those covers don't seem to have a role in that.

That being said I'm back from a good test drive through a lot of twisty roads and I still heard SOME rattle coming from the same area. It was a LOT less than usual and very hard to trigger. This might be the cowl itself since it clicks against the windshield as we noted earlier. Only way to know is to remove the cowl but I will need dealer help with this. Will try stuffing it some more with cardboard and if that doesn't work it's off to the dealer to check out the cowl.

[ft1330]

Update time. It's not the cowling. Bummer. I have everything removed at this point, the big rubber seal, the plastic covers, the wipers, the cowl, the engine cover, and some other pieces of plastic garbage around the engine bay. The rattle is still there under the right conditions.

I've clearly identified that it happens mostly between 2000-2500 rpm under rather pronounced acceleration (not slow but not WOT, just intermediate acceleration). It's most noticeable going uphill and while turning. I put the auto transmission in M mode and just manually shift to stay in that rpm band and I can reproduce it rather consistently.

The other day I didn't have the rattle the whole afternoon. Then I decide to change my steering wheel position and guess what, the rattle started again after that. It might be steering related.

Took a drive with the foreman at my dealership, we heard the rattle some and he agreed it was odd. A hard admission by any BMW standards I'm sure.

It's off to the dealership next week...

[TonyS]

Originally Posted by ft1330

Update time. It's not the cowling. Bummer. I have everything removed at this point, the big rubber seal, the plastic covers, the wipers, the cowl, the engine cover, and some other pieces of plastic garbage around the engine bay. The rattle is still there under the right conditions.

I've clearly identified that it happens mostly between 2000-2500 rpm under rather pronounced acceleration (not slow but not WOT, just intermediate acceleration). It's most noticeable going uphill and while turning. I put the auto transmission in M mode and just manually shift to stay in that rpm band and I can reproduce it rather consistently.

The other day I didn't have the rattle the whole afternoon. Then I decide to change my steering wheel position and guess what, the rattle started again after that. It might be steering related.

Took a drive with the foreman at my dealership, we heard the rattle some and he agreed it was odd. A hard admission by any BMW standards I'm sure.

It's off to the dealership next week...

So it's not just me then. It just shows how difficult this noise is to pin down, doesn't it? Mine does it under exactly the same circumstances as you mention too. It's definitely worse under engine load and when going uphill (which of course increases the engine load). My car is booked in to the dealers again on the 7th.