My 1998 BMW 540i seems to have a vibration that I can feel in the accelerator in my foot and also in the steering wheel. I had new Michelins put on the car in October. I noticed that the drive was a bit stiffer, but no vibration. In November, I had an Inspection II and a diagnostic for a rough idle. I had a leak in the cooling system, which was repaired. I also had some gaskets replaced in the engine at that time, since it was taken apart. I got a new thermostat during this repair. I did notice the vibration after this repair, but just took it back now after the holidays and a trip out of the country.
My shop balance all the wheels, since they were all a little off. Although that did fine tune the driving, I still feel some vibration in my foot through the floor, especialy at 60 or eighty or accelerating from 60 to 80. I don’t feel it when I am braking.
Can anyone suggest a possible cause?
Thanks.
A typical first step for a problem like this is to switch the front and back wheels and see if the vibration moves or changes. If so, then you know it’s something with the tires or wheels and not something with the suspension.
So, is it most likely tires or suspension? It’s such a fine vibration, not a shimmy in the steering wheel. The car used to be so smooth. Could it be transmission or engine?
If the problem goes away when braking, it’s probably not tires or suspension - especially if it is worse under acceleration.
This is probably drivetrain related - possibly CV or U joints.
The mechanic said my bushings are good. I don’t know if they examined other components of the suspension.
Also, when the car is in park and the parking brake is on, I rev the engine to 1000 or 2000 rpms, there is a cyclical shudder in the car, like something that is supposed to be round is now elliptical, or there is just uneven firing in the engine. I don’t know if this is part of it, or something else.
I can feel a vibration in the steering wheel when the car is idling which is about 500 rpms. The vibration is very discernable throughout the car at 80mph.
Once or twice, I have noticed that the vibration rattles something around the dashboard, particularly when accelerating.
I do get a bit of a brief shimmy, sometimes when braking or accelerating on and off freeway ramps.
The car doesn’t accelerate through its 6 speed automatic transmission as smoothly as it used to. Could this be oxygen sensor or transmission related, or would these be issues separate from the vibration?
Thanks.
I would have all of the engine and transmission mounts carefully inspected. “Carefully” b/c it is often hard to identify milder mount problems - its only obvious if they are really bad or if they completely fail (as in break).