[E90_boostjunky]

alright so ive had my car for a year now, and everytime i start it up in the morning (cold start) it makes a loooooooud rattling noise at first, then it makes another rattle when the other exhaust kicks in. anyway ive read and researched that it could possibly be normal, but ive also read that its the wastegates, i talked to my service advisor a while back, he said its normal and wouldnt believe me, another thing noise i noticed today was when i have the air blowing and i turn my steering wheel to the left i hear like a high pitch chirping noise. any ideas? let me know please thanks! I have an oil change appointment this thursday i was thinking of making a video of the rattle on cold start and showing it to the mechanic. belows a video i found on youtube of the similar problem i have, the guy had his wastegates replaced and his left exhaust..

[WhyCry]

My car sounds exactly like that during a cold start. So i'm pre sure it's normal. Either that or I gotta get my bimmer checked out too, lol.

[E90_boostjunky]

Originally Posted by WhyCry

My car sounds exactly like that during a cold start. So i'm pre sure it's normal. Either that or I gotta get my bimmer checked out too, lol.

yeah im tired of it, it seriously makes me feel like my cars going to break, if you watched the whole video, that guys noise went away. Sucks your in Canada cuz we got Extended warranty on turbos 82K/8years

[WhyCry]

Originally Posted by E90_boostjunky

yeah im tired of it, it seriously makes me feel like my cars going to break, if you watched the whole video, that guys noise went away. Sucks your in Canada cuz we got Extended warranty on turbos 82K/8years

Well my bimmer's out of warranty atm and I don't want to pay $6000 for replacement turbo's so i might just get extended warranty and then after a month take it in to get the rattling noise checked out :P

[bbbuzzy]

^^^ and people wonder why an extended warranty costs so much. Nice

[xG35c]

I think you're hearing an air pump that kicks in during cold starts. The ones in BMWs always seem noisy - I complained about it in my wife's X3 and they first told me it was normal, but eventually replaced it, much quieter now!

Actually just listened to the video again - if you're mean those momentary metallic rattles, not so sure it's the air pump...

[WilliamS]

There are a few noises that start with a BMW, first you have the DTML pump which does a quick pressure test on the fuel tank to see if there are any leaks. Then you fire up the car and if its a 330 or 335 you will hear the exhaust valve closing (metal rattly sound). Then if its a coupe the seat belt hand ups, a few tones, then the radio. Its a poorly designed orchastra of annoying. Mine has a rattle at high speeds on the highway coming from the back seat area.

[5soko]

What your hearing is the exhaust flap closing and opening. Your sounds to be a little extra loose.

What you can do to cure this problem is the 'golf tee mod'.. This will disable the valve from opening and closing. I have disabled my valve since i bought my car, i pinched the black wire that goes to the actuator on top of the exhaust tip that was in the video, and zip tied it. This stops air going to the actuator, hence stopping the closing/opening action.

Or tell the dealer that your valve for the exhaust is bad and see if they will warranty it, problem not.

[Doctor///M]

Thta's anything BUT normal. Aren't these things (wastegate rattle and turbos) still covered by BMWNA, regardless of warranty status?? I'd go to another dealer.

[Dark_Knight_335]

Originally Posted by Goofyguy

There are a few noises that start with a BMW, first you have the DTML pump which does a quick pressure test on the fuel tank to see if there are any leaks. Then you fire up the car and if its a 330 or 335 you will hear the exhaust valve closing (metal rattly sound). Then if its a coupe the seat belt hand ups, a few tones, then the radio. Its a poorly designed orchastra of annoying. Mine has a rattle at high speeds on the highway coming from the back seat area.

Yup! Same damn issue, but mine comes from behind me on the driver side almost as though there's a piece of aluminum rattling in the damn quarter panel in the back...
Oh and then there's that bang that sounds like somebody shot my rear quarter panel with a shotgun whenever I hit rough pavement.
Then again mine is a convertible so I'm assuming I am subject to all types of rattling and shit based upon the fact that my roof folds and goes into the trunk.
When the top is down I can't hear any of of it anyway...meh.

[cmyk]

Originally Posted by 5soko

What your hearing is the exhaust flap closing and opening. Your sounds to be a little extra loose.

What you can do to cure this problem is the 'golf tee mod'.. This will disable the valve from opening and closing. I have disabled my valve since i bought my car, i pinched the black wire that goes to the actuator on top of the exhaust tip that was in the video, and zip tied it. This stops air going to the actuator, hence stopping the closing/opening action.

Or tell the dealer that your valve for the exhaust is bad and see if they will warranty it, problem not.

My car sounds exactly like this at startup and that's what I always assumed it was, too.

I have thought about having it looked at at one of my maintenance services but I have a modified exhaust so I figured they would just blame it on that

It sounds like a chain rattling.

[Sunny31]

I had the exact same rattle/chainsaw noise on start up. Took it in the dealership just before warranty expired. The ended up replacing the left side exhaust and the problem was fixed.

[E90_boostjunky]

I made a video this morning you can hear a slight quiet rattle at first, and then a loud rattle to end with.

[E90Company]

ALOT of mis-information here:

That is the drivers side exhaust flapper that is shut during a cold start. It's purpose it debated, but most believe it is to quiet down the cold start exhaust, or warm up the cats quicker.

If you don't want to hear it rattling anymore, you can disable the flapper by doing the "golf tee mod" (Search the DIY). Reach into your trunk panel on the drivers side, and disconnect the connector. This does throw a shadow code, but it's nothing to worry about at all. If you brought your car into the dealer, this is what they will do anyways to "fix" it.

[marshall834]

Originally Posted by Goofyguy

There are a few noises that start with a BMW, first you have the DTML pump which does a quick pressure test on the fuel tank to see if there are any leaks. Then you fire up the car and if its a 330 or 335 you will hear the exhaust valve closing (metal rattly sound). Then if its a coupe the seat belt hand ups, a few tones, then the radio. Its a poorly designed orchastra of annoying. Mine has a rattle at high speeds on the highway coming from the back seat area.

I think I hear that pump every time you open a door, unlock your doors, correct? Small humming sound.

I'm not so sure I've ever heard the exhaust flap closing. I'll have to pay attention to that.

Regardless, good info, thanks!

[WilliamS]

Originally Posted by marshall834

I think I hear that pump every time you open a door, unlock your doors, correct? Small humming sound.

I'm not so sure I've ever heard the exhaust flap closing. I'll have to pay attention to that.

Regardless, good info, thanks!

Yup when you open the door you can hear it. Mine has failed a few months back I will get around to repacing it, after I found out its function I just set my JB4 to autoclear the code it would set off and Ill worry about it when I have the time to care.