E46 Troubleshooting

My 01 330ci recently developed a weird vibration when turning right at high speeds, a kind of vibration that in all my years of working on driveability issues as a pro wrench I never came across. It only happens on relatively high speed turns, like a freeway on ramp, or even a curvy freeway. What happens is that something starts vibrating like a very out of balance tire might, only faster, but I don't feel a thing in the steering. It seems to be coming from the right front whenever the suspension gets partly unloaded. I checked everything out last night and didn't find anything. So just for the sake of ruling it out, I cross rotated the front tires. This morning on my way to work it was worse if anything (probably was just the same, but it felt worse). Any ideas?

Does it present itself under braking?

I would recheck the front control arm bushings. The ones in the "lollipops".

They are $28 each from BMW.

In reply to Slippery:

I just replaced that entire control arm about 6 months ago, and I did check the bushings thoroughly last night. They still look brand new. And no, it doesn't present under braking. Everything I've learned over the years indicates its coming from the right front. I only say that because I happen to have a lot of experience in diagnosing these types of problems. But I wonder if it could possibly be coming from the rear? There's a lot of things about this car that are different than most I've worked on. Could it be fooling me? idunno. But I could sear its in the right front. I just can't see it being something that wouldn't be felt in the steering wheel or brake pedal. I can feel it with my leg in the center console.

In reply to bravenrace:

Okay, looking back to refresh my non-memory, I realize now that the bushings are not part of the control arm, and I can't remember if I replaced those as well or not. I did check them last night, and they seemed fine, but is there a particular way they should be checked?

Check for play in the ball-joints (I know those were replaced with arms, but still) and tie-rods.

In reply to NEALSMO:

Already did that, and everything is tight.

Also check:

Take a good look at the wear on the tire. You got a bubble or a band coming undone maybe?

Wheel bearing, play at the inner tie rod? Steering rack? Engine mount?

Butt dyno not calibrated... vibration coming from somewhere else: Get a passenger in the back seat.

Long shot: Vibration in swaybar end link or binding/releasing in a sway bushing when the bar is loaded up?

wheel bearing.

Mark it.

Huckleberry wrote: Also check: Take a good look at the wear on the tire. You got a bubble or a band coming undone maybe? Wheel bearing, play at the inner tie rod? Steering rack? Engine mount? Butt dyno not calibrated... vibration coming from somewhere else: Get a passenger in the back seat. Long shot: Vibration in swaybar end link or binding/releasing in a sway bushing when the bar is loaded up?

Already done, but thanks.

golfduke wrote: wheel bearing. Mark it.

Not sure what you mean by "Mark it". I did check the wheel bearing for play and it's tight. Doesn't make any funny sounds when I rotate the tire either.

I think with your experience you would notice a wheel bearing. They would not necessarily make any noise if they have no load on them, but driving and turning would give you a humming noise.

I believe the front control arm bushings are liquid filled. On my M3 they are deep and covered by a big metal splashguard not sure on your car. I would lift that wheel and try and pull/push and see if there is any movement there. Maybe use a crowbar.

I would rotate the tires just because if you haven't ... but assuming you have checked every single thing with a pivot or rubber joint in the suspension I'd question if the front damper was a tad floppy at the end of it's travel. Hang a go-pro pointed at it and see what it does. Is the top of the shock mount able to rotate or is it binding against the spring?

You could have play in the steering rack that only shows up under load, causing one of the tires to oscillate a bit (probably FL). You wouldn't necessarily feel that in the steering wheel, because the movement wouldn't come back up the steering haft. I had something similar after replacing the entire front suspension and bearings. A SpecE46 guy told me it isn't uncommon, rack seals have a tendency to rot.

my e46 did the same exact thing on highway turns and it was a worn out control arm bushing

My E39 did this and it turned out to be a worn out thrust arm bushing.

In reply to westsidetalon:

Thanks. I'm starting to think that as well, but haven't had any time to check it out. Hopefully I'll be able to this weekend. I'll report back.

Were you able to figure this out?

bushings balance wheels and tires

In reply to Slippery:

Yeah. It was the drivers side lower control arm ball joint.

Shut, it only lasted 6 months?? Sucks but at least you found the problem.

Wow, that's surprising. What control arm did you have in there? I sprung for the Meyle HDs, supposedly they are a little less delicate. Are your roads particularly rough?

It's the other control arm. It was the passenger side I had just replaced. I checked the drivers side when I did the other one and it was fine, so I guess it went bad since then.