Front end rattle making me nuts!!

[CrimsonBrian]

Hey BMW folk,
I have been plagued by a rattle coming from the undercarriage of my car for the past few months now. I was fairly sure that it was the rear shock mounts, so I had them replaced along with the rear shocks (which I think had only been replaced once in the 135k). So, now the back of the car is silent but the front rattles like on surface streets. On the highway, there really isnt too much of a rattle, but it will get going if the road gets a little rough. I dont feel anything weird in the steering, there is no shimmy, and the car corners and brakes just fine. I am reluctant to go ahead and just replace the front shocks, if this is not going to fix it. Any ideas what I might be dealing with? Thanks so much!!

Brian

[Russell]

check front sway bar links- rattle when worn

[632 Regal]

I have a rattle on the front driver side of mine too, inspected everything and it all looks good. I was hoping the new sway bar links loosened up but that wasnt it. sounds almost like a loose hubcap, light metalic sound. I tried checking the control arm but was unable to get any play out of it either with weight on it or in the air. hmm.......

[AllanS]

I just switched to Bilsteins the other day (or 3 days, as it were- pain in the ass), and found out what had caused my mysterious rattle from the passenger's side- the shocks on the passengers side, both of them, were totally shot. The stanchions would slide up and down with almost no resistence, so essentially the spring had free reign.

After replacing all the shocks, the noise, and of course, sloppy handling, were gone. I just drove 4 hours on i87 yesterday and it was like night and day.

[Phil Sanderson]

Check your front strut collars as in this pic to see if they are loose. Can be an annoying noise. Pic is from a previous post but I don't know who to credit for solving this problem - sorry.

Phil

[CrimsonBrian]

Thanks everyone, I am going to see if I can chase this thing down!

[4byr]

The rattling could indeed be what was posted (sway bar, struts) but don't count out motor mounts. They have been known to basically disintegrate over time. Mine had 60 K on them and they were in pieces. I didn't know what was clunking when I turned or accelerated. Take a look at yours. Lift the motor slightly from the oil pan. You should be able to see a problem lifting it just a little bit. Do you get vibration at speed? THis could be an indication of a problem with the control arms.

Good luck

[andyman32]

The same thing happens with my car, but I've been hesitant to post because it could be so many things.

There IS this rattle in my car, sounds like it's coming from under the car or in the front wheel well on the passenger's side. I thought it might be one of the little plastic fittings between the fog lamps, so i jammed some electrical tape up in there. That didn't help. Then I noticed that one of the plastic fittings inside the wheel well on the passenger's side had broken a little and come undone from the plastic retaining screw, but I popped it back under and it didn't fix it.

It's also starting to drive ME nuts. It's pretty pronounced when you're standing outside the car. It is not a "mechanical" rattle, as it is highly irregular. I visually scanned everything on the shock tower and steering knuckle when i had the car up on ramps yesterday and I can't find anything.

At this point I'm at a loss - but that strut collar looks promising. I wanted to replace my shocks anyhow. Maybe this makes a good excuse to proceed. :-D

[CrimsonBrian]

Listen, you and I can join the nuthouse together; maybe we can get some kind of group discount. I am not that mechanically inclined, but I do have a Bentley (the manual, not the car unfortunately), and so I was looking at the pictures of all the suspension components. I am a little hesitant to simply drop it off at my mechanic and say, "Fix this rattle!" He is very good and very honest, but I am concerned he might just pop in new shocks and struts and have it end up costing me more than I wanted to spend.

The car does not pull, drag, or vibrate at all, which makes me think that it must be a minor part. It does sound like there is some rubbing though, because if I am driving with the windows down and the radio off I can hear it. It sounds like something in the wheel though because it slows down and speeds up with the car. Probably something to do with the brakes, which might be unrelated. Thanks for all your help, guys. I'll definitely let you all know what it ended up being. I might brave my mechanic later this week. I might also pop into Click-And-Clack's (those NPR car talk guys) shop which is only several blocks from me. They are really nice and know what they are talking about.

[charlie]

The rattling could indeed be what was posted (sway bar, struts) but don't count out motor mounts. They have been known to basically disintegrate over time. Mine had 60 K on them and they were in pieces. I didn't know what was clunking when I turned or accelerated. Take a look at yours. Lift the motor slightly from the oil pan. You should be able to see a problem lifting it just a little bit. Do you get vibration at speed? THis could be an indication of a problem with the control arms.

Good luck

my motor mount on the drivers side (I wasn't sure what I was looking at- liquid filled I guess) but it was pretty saturated (wasn't sure if it was engine mount itself or P/S lines dripping on it). I just replaced thrust arms, and get a bit of a clunk sometimes on a turn or acceleration. I had an inkling that it was motor mount, how to be sure? BTW, 1995 540i