E46 BMW Social Directory E46 FAQ 3-Series Discussion Forums BMW Photo Gallery BMW 3-Series Technical Information E46 Fanatics - The Ultimate BMW Resource BMW Vendors General E46 Forum The Tire Rack's Tire Wheel Forum Forced Induction Forum The Off-Topic The E46 BMW Showroom For Sale, For Trade or Wanting to Buy

Welcome to the E46Fanatics forums. E46Fanatics is the premiere website for BMW 3 series owners around the world with interactive forums, a geographical enthusiast directory, photo galleries, and technical information for BMW enthusiasts.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact contact us.

Go Back   E46Fanatics > E46 BMW > General E46 Forum

General E46 Forum
This is the place to get answers, opinions and everything you need related to your E46 (sedan, coupe, convertible and wagon) BMW!

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 12-28-2012, 09:20 PM   #1
2003silver330i
Registered User
 
Join Date: Feb 2012
Location: N. Las Vegas, NV
Posts: 1,595
My Ride: 03 BMW 330i
Reinforcement plate knock?

I have been hearing a knocking sound coming from under the car for months so I decide to jack it up and get under there to track down the noise. The knocking noise is coming at the back of the oil pan that is covered by the reinforcement plate. The knocking sound is not really noticeable with the car in park or neutral. However when you throw it in drive or reverse you can hear get louder. Is it possible that the engine is knocking against the reinforcement plate or am I looking at a spun crankshaft bearing?
2003silver330i is offline   Reply With Quote
Ads by Google

Guests, get your FREE E46Fanatics.com membership to remove this ad.
Old 12-28-2012, 09:23 PM   #2
M1992
Registered User
 
Join Date: Nov 2009
Location: In an epic world.
Posts: 122
My Ride: 02' E46 330i
It could be a split differential. I had the same problema couple years ago, turned out my differential split in half. Luckily I got it replaced with a warranty, got a refurbished one installed. WHen the noise first started I too thought it was some sort of bearing, possibly a wheel bearing, but no I guess the differential just gives out after some time. Have you been driving the car hard with lots of people in it?
__________________

Quote:
Originally Posted by captjones
my dad used to pat me on the head when i had very short hair & said:
"son, u'd make a fine toilet brush"
M1992 is offline   Reply With Quote
Old 12-28-2012, 09:56 PM   #3
2003silver330i
Registered User
 
Join Date: Feb 2012
Location: N. Las Vegas, NV
Posts: 1,595
My Ride: 03 BMW 330i
The car has 140K miles on it now and my wife is the only one that drives it. Not sure about the previous 130K miles of the car's life though. If it was the differential wouldn't the noise be towards the back of the car?

Last edited by 2003silver330i; 12-28-2012 at 10:23 PM.
2003silver330i is offline   Reply With Quote
Old 12-28-2012, 10:25 PM   #4
bimmernut3
Registered User
 
Join Date: Sep 2012
Location: Asheville, NC
Posts: 287
My Ride: '05 330cic, '01 540i
Quote:
Originally Posted by 2003silver330i View Post
I have been hearing a knocking sound coming from under the car for months so I decide to jack it up and get under there to track down the noise. The knocking noise is coming at the back of the oil pan that is covered by the reinforcement plate. The knocking sound is not really noticeable with the car in park or neutral. However when you throw it in drive or reverse you can hear get louder. Is it possible that the engine is knocking against the reinforcement plate or am I looking at a spun crankshaft bearing?
Could you be a little more specific about the noise? Is it RPM dependent? Do you hear it all the time or only when driving? or only when shifting to "R" & "D"? If it increases as you drive, I would be looking at the drive line; i.e. flex joint or centering bearing. However if it makes the noise while sitting still, it wouldn't be these items.
If it does it when shifting, have you checked motor & transmission mounts?
Please post reply's to the above & we can go from there.
__________________
'05 330ci

[IMG][/IMG]
bimmernut3 is offline   Reply With Quote
Old 12-28-2012, 10:27 PM   #5
2003silver330i
Registered User
 
Join Date: Feb 2012
Location: N. Las Vegas, NV
Posts: 1,595
My Ride: 03 BMW 330i
Would noise from a lifter travel that far down to the oil pan?
2003silver330i is offline   Reply With Quote
Old 12-28-2012, 10:36 PM   #6
2003silver330i
Registered User
 
Join Date: Feb 2012
Location: N. Las Vegas, NV
Posts: 1,595
My Ride: 03 BMW 330i
Quote:
Originally Posted by bimmernut3 View Post
Could you be a little more specific about the noise? Is it RPM dependent? Do you hear it all the time or only when driving? or only when shifting to "R" & "D"? If it increases as you drive, I would be looking at the drive line; i.e. flex joint or centering bearing. However if it makes the noise while sitting still, it wouldn't be these items.
If it does it when shifting, have you checked motor & transmission mounts?
Please post reply's to the above & we can go from there.
The car is an automatic. You can't hear it until you put a load (drive or reverse) on it. When accelerating it almost sounds like pinging/detonation and gets worse with more load and goes away immediately after getting off the accelerator. The sound is most noticeable when taking off from a slow move or dead stop. Also, it does make the noise with the car not moving however the car must be in drive or reverse to hear it.

Last edited by 2003silver330i; 12-28-2012 at 10:40 PM.
2003silver330i is offline   Reply With Quote
Old 12-29-2012, 03:21 PM   #7
TitaniumCranium
/// Limitless
 
TitaniumCranium's Avatar
 
Join Date: Apr 2005
Location: Seattle / Sequim
Posts: 3,216
My Ride: 2002 BMW 330Ci
Remove the reinforcement plate and drive a mile or so to see if that's the source of the noise. It's not recommended to drive without the plate but a mile or so isn't going to cause the car to split in half, unless you've... wait.

There is another item that would cause the oil pan to come into contact with the reinforcement plate. A broken engine mount - the aluminum part. Or a seriously failed rubber mount. The aluminum part failed on my car a couple of years ago when I hit a parking lot speed bump harder than I should of. It was the same color as the asphalt so I didn't see it.
__________________

/// MODS
/// Auto => 6-Spd Manual Conversion | Apex EC-7 | Koni/Ground Control Coilovers | Vorshlag Camber Plates | Meyle HD LCA | PowerFlex bushings | GruppeM rep CAI | Shark Injector | 6000k HID's and Fogs | BMW European MTechII | BMW Performance Shifter | ACS Mirrors and Rear Spoiler ///
TitaniumCranium is offline   Reply With Quote
Old 12-29-2012, 03:40 PM   #8
bimmernut3
Registered User
 
Join Date: Sep 2012
Location: Asheville, NC
Posts: 287
My Ride: '05 330cic, '01 540i
I would definitely check your motor mounts, which is an easy visual check. Why don't you try having someone sitting in the car, parking brake set, foot on the brake & shift from drive to reverse with the engine on while you look at the engine with the hood up. Does the engine shift up or down as the gears are shifted? It will a little normally but if bad or broken, the motor will move more than normal. Your mounts are located about in line left to right where your strut towers are WAY down toward the bottom. The drivers side is a bit easier to see. Use a flash light if needed. Here's a link that will show them better.
http://forum.e46fanatics.com/showthr...ghlight=mounts
__________________
'05 330ci

[IMG][/IMG]
bimmernut3 is offline   Reply With Quote
Old 12-29-2012, 03:43 PM   #9
bimmernut3
Registered User
 
Join Date: Sep 2012
Location: Asheville, NC
Posts: 287
My Ride: '05 330cic, '01 540i
I found this video to take a look at for the broken mount.
__________________
'05 330ci

[IMG][/IMG]
bimmernut3 is offline   Reply With Quote
Old 12-30-2012, 04:25 PM   #10
2003silver330i
Registered User
 
Join Date: Feb 2012
Location: N. Las Vegas, NV
Posts: 1,595
My Ride: 03 BMW 330i
After further investigation the plate is fine. The knock is probably a lifter because once you put a load on the engine around the 2500-3000RPM area the noise completely goes away and never comes back until the car is shutoff and restarted.
2003silver330i is offline   Reply With Quote
Old 12-30-2012, 04:30 PM   #11
ac_2007
Registered User
 
ac_2007's Avatar
 
Join Date: Apr 2010
Location: Toronto
Posts: 7,217
My Ride: E46 - M3 & 325i
Quote:
Originally Posted by M1992 View Post
It could be a split differential. I had the same problema couple years ago, turned out my differential split in half. Luckily I got it replaced with a warranty, got a refurbished one installed. WHen the noise first started I too thought it was some sort of bearing, possibly a wheel bearing, but no I guess the differential just gives out after some time. Have you been driving the car hard with lots of people in it?
I thought of this song when you posted.


__________________
ac_2007 is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Censor is ON





All times are GMT -5. The time now is 11:20 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
(c) 1999 - 2011 performanceIX Inc - privacy policy - terms of use