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-   -   #VibrationTrouble (http://forum.e46fanatics.com/showthread.php?t=967625)

SilverThreeTwoFive 01-25-2013 12:25 PM

#VibrationTrouble
 
So, I have been noticing a kind of low frequency vibration coming from the rear of my car.

To start off: my car is a 2002 325i A/T with 141k miles.

Symptoms: Low frequency vibration, seems to be coming from the back of the car. Can not be felt in steering wheel, usually behind you or sometimes under the seat. It is stronger under moderate to hard acceleration, but if it starts to rumble and I let off the throttle, the rumble goes away. It can be felt as a mild tremor under casual acceleration. It also seems to be worse after the car has been driven a mile or so after a cold start. The vibration is strongest from 25-35 mph in any gear and cannot be reproduced above 40mph. So it seems to be entirely speed dependent and load dependent.

Tentative speculation: I am guessing it has something to do with either a worn guibo, worn CSB, or both. I know that all my struts are worn and will be replaced soon but this doesn't sound like a strut problem. Also I don't believe it's a wheel and tire problem as this happened on an old set of tires as well but I can rotate them and see if the vibration follows the wheels.

Any other suggestions and advice? I have not gotten under to give the guibo and CSB a look yet, just so you know that as well.

WDE46 01-25-2013 12:28 PM

My car does this too at exactly those speeds. I can replicate it at 38 mph EVERY time I want to when the car is warm going up a slight incline. I believe mine is the guibo (hopefully not the CSB), but I haven't replaced it. That's really the only thing I can think of. My guibo looks fine and you can't really inspect the CSB, but I may just do both at once when I get the chance.

lcoleman 01-25-2013 01:18 PM

Shocks in the rear, not struts. Could be something along the driveshaft, or wheel bearings. Does it change when turning?

E46Moonlight 01-25-2013 01:23 PM

Check transmission mounts and diff mounts. thats can cause the guibo and CSB to start acting up.

SilverThreeTwoFive 01-25-2013 02:30 PM

Yeah I know it's shocks in the back...I just didn't bother to differentiate them when I wrote it, lol. I don't believe it changes when turning which would kind of rule out bearings. I've also read that bearings don't typically start making noise under acceleration only. It also doesn't change pitch and get louder at higher speeds. It literally disappears above around 40mph. I talked to our BMW tech at the shop I work at and described the symptoms I wrote above and he concluded it was most likely a worn Guibo or CSB as well. He's been working on Bimmers for twenty years or so and he's nailed every problem my car has had so far so I'm gonna listen to him and check out the guibo. But while I'm down there I'll check the tranny and diff mounts. How do you suggest I check those, E46Moonlight?

E46Moonlight 01-25-2013 02:37 PM

While under the car you could visually inspect them. See if there's any wear in them, if so replace. Cause if you get a new guibo and CSB with a bad trans mount the new guibo and CSB can wear way faster than normal

SilverThreeTwoFive 01-25-2013 02:50 PM

Cool. I'll check all that out! Thank you guys for your responses!

Solidjake 01-25-2013 02:56 PM

Lmao, is this instagram that we need hashtags? :rofl:

SilverThreeTwoFive 01-27-2013 03:33 PM

I rotated my tires today just for the hell of it. I don't remember the vibration happening on my old tire setup but it wouldn't be the first time I was wrong. So I'll drive it and report my findings. Hopefully I hear a vibration in the front now! How often can you say that?

SilverThreeTwoFive 01-27-2013 11:05 PM

Well, I rotated the tires and it seems like I have more vibration up front now than in the rear and that vibration is felt mostly in the steering wheel and more frontwards of the car now... Maybe it's something with the wheels and/or tires. I meant to say in my last post that I thought I remembered having this vibration/rumble with my old tires too. But it could be a bent wheel or something throwing it off combined with my old suspension allowing things to bounce and vibrate too much? I also got under and took a look at the guibo and it doesn't look to have any wear that I can see. No cracks in the plastic or anything. I wasn't able to look at the CSB as that would have involved more time. I'll drive it a few more days to make sure I'm really feeling a difference and not just going off of a confirmation bias or anything.

Gheybe 01-27-2013 11:18 PM

Came in here to make fun of you for putting "#" on your title.

SilverThreeTwoFive 01-27-2013 11:20 PM

Haha, yes it was supposed to be funny.

MJLavelle 01-27-2013 11:45 PM

Vibrations within certain speed ranges can be caused by tires. Now, if the two of you who mentioned this in this thread have the same brand and model of tire, that would be perfect. But probably not.
First Gen Miatas were notorious for getting a vibration from 40-60mph with BFGoodrich tires.
My e46 came with General (XPS?) tires. They had a bad vibration below 40 mph. I really thought I had other suspension issues, but it went away completely when I put on Michelin PS2's.
But don't discount one of the more simple possibilities before digging in and buying parts.

lcoleman 01-28-2013 12:12 AM

Most tire vibration is a balance or runout issue. Have them balanced. They should be able to tell you if your wheel is bent, just mention it.
Quote:

Originally Posted by MJLavelle (Post 15102212)
First Gen Miatas were notorious for getting a vibration from 40-60mph with BFGoodrich tires.

The "60mph shimmy" is pretty notorious, regardless of tires. It's mostly a chassis issue; mine went away when I installed a roll bar.

SilverThreeTwoFive 01-31-2013 12:42 AM

Yeah, after driving the car a few days now after the tire rotation I really feel like most of what I was feeling is now in the front. It feels like there are more vibrations now in the steering wheel and the vibrations feel and sound to be coming more from the front. If I lean back towards the back of the car while I run through the 25-35mph range it doesn't seem to be making any low frequency noises in the back anymore. The tires are Kumho Ecsta AST's which are a cheap tire, I believe. I feel like it's a combo of a poorly balanced tire paired with my blown suspension components giving me vibration problems or something. I just got the last of the suspension pieces yesterday from Bavauto so it will have all new struts, SHOCKS, mounts, LCAB's, etc.. I will also have the wheels checked at work and see if it is off. Blah.... E46's do not seem to age well

HacksawMark 01-31-2013 10:38 AM

Quote:

Originally Posted by SilverThreeTwoFive (Post 15114262)
E46's do not seem to age well

Only if you don't maintain them and/or drive them that there's no tomorrow.

SilverThreeTwoFive 01-31-2013 10:44 AM

I just bought it a few months ago with 137k miles. I'm not going to complain too much. It's still in pretty great condition. I've only had to fix the common problems so far. I'm just hoping my problem is a wobbly tire and worn suspension and not a guibo and/or CSB or something else. It's been expensive to get everything fixed but I love the car and when it's done it will feel awesome to have everything all buttoned up.

330iPilot 01-31-2013 10:45 AM

Any car at 141K is going to need suspension components replaced.

SilverThreeTwoFive 01-31-2013 10:47 AM

Agreed. That's why I've got all the new suspension parts sitting here on my bench at work!

bmwTuner1 01-31-2013 06:43 PM

Quote:

Originally Posted by Solidjake (Post 15096037)
Lmao, is this instagram that we need hashtags? :rofl:



Quote:

Originally Posted by Gheybe (Post 15102149)
Came in here to make fun of you for putting "#" on your title.

:clap:


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