2009 X5 (E70) noise from front right while steering, braking and driving (solved)

[BMWerkeUS]

Hello,


We had been working on identifying a screeching noise coming from the front passenger side of the vehicle. Noise is heard while steering (at low speed), braking, acceleration (from stop) and going over bumps for my 2009 X5 (E70) 35d.

We had a bad sway bar end link and we were thinking that it was the source of the problem.



We replaced it but the noise was still there.

First thing we did was to do a general inspection of the suspension components looking for loose parts, torn bushings, torn boots, loose nuts/bolts or brackets. Everything looked fresh and tights.

Then we listened for the noise in the garage with the engine running. I simply watched the suspension components while a family member turned the steering wheel left and right. The noise was audible but was difficult to pinpoint. Then, I put my finger on the components as we continued the test (be VERY VERY VERY careful in doing this you may get your hand/finger caught between the moving parts. Move the steering wheel very little at a time. ). I felt the most vibration on the wishbone. Vibration became more intense as I approached the ball joint. We verified that the vibration is indeed most intense around the ball joint but the wishbone looked very fresh and the boot looked fresh. If I were to make a guess, I would say that this part did not go through a winter yet.

In any case, the state of the part and the boot made me doubt that the wishbone or the ball joint could be the source. I did a close inspection of the boot around the ball joint and found a small crack of about 5mm in length. I decided to inject some WD40 inside the boot using a syringe. We took it for a test drive and noticed that the noise from steering was reduced but the noise from bumps on the road, braking and acceleration were still there. Next, we put actual grease in the boot using the same syringe.






Took it for a test drive and the steering noise was almost completely gone but the noise from bumps etc. were still there.

Following morning, I got a stethoscope from Walgreens for $10 (I took my son’s car and you will see why this detail is important in a little bit). We jacked the car up and put it on jack stands and took the tire off.

Then, we jacked up the suspension components from the wishbone and brake rotor using the hydraulic jack and released it quickly while listening for the source of the noise using the stethoscope. To our surprise, we could not hear any noise while jacking it up or after the release. I thought that we would have to find a way to listen for the noise while driving the car. We put the tire on and lowered the car. Once again, we were surprised how quiet it was.

Then, we shook the car from the fender and front bumper but there was no sign of any noise. I thought this deserved another test drive. We took the car out for a drive and more than 95% of the noise was gone. I think what happened is that overnight WD40/grease made its way around the ball joint and hence the improvement overnight, We put in more grease and drove it more and now for all intents and purposes the noise is gone.

I am going to drive it for a week and see how it goes. If it stays as is, I may just seal the boot using Flex Seal and call it done. I am thinking this will be OK since the wishbone was installed recently (under the previous owner) and perhaps they tore the boot while installing.

In any case, we now know the source of the problem and the worst-case scenario is to replace the wishbone (OEM part is $73.99 from here).

For me at least, the lessons learned are:

1. A close inspection of the suspension components is a key and the looks of the parts can be deceiving
2. Start searching for the source of the noise that can be reproduced while car is not moving and tackle that first for it may also be the source of the noise observed while the vehicle is in motion
3. Lubricants can be your friend in identifying the source of the noise but need to use the right type and give it a bit of time (or help) for the lubricant to make its way around the moving parts.

If you must listen for the noise while driving, you might want to look into STEELMAN Chassis Ear here for example. I understand they come in wired as well as wireless.

[heatmizr]

Good detective work!

[BMWerkeUS]

Originally Posted by heatmizr

Good detective work!

Thanks heatmizr!

[BMWerkeUS]

Update:

It has been one week since my last post and the noise is completely gone. During the week I inspected the boot twice and noticed that some grease was coming out of the crack. We decided to put in some more new grease and seal it using Flex Glue that we picked up at a local Walmart for $12.88:



Before applying the glue, we made sure that the crack itself and the area around it is clean. For this purpose we used a brake cleaner that we already had:



We had to apply the break cleaner a few times and wipe of any grease that was in the crack. After the last application of the brake cleaner, we let it evaporate and did not do any wiping. As far as we could tell, the surface was pretty clean. It has been 17.5 hours and the car is still on the jack stands and this is what the area now looks like:



The glue is white instead of black. I think it will work out fine since we could easily tell if the red grease starts to seep out. Once the glue cures for 24 hours, we will take the car out for a drive around the neighborhood and see if any grease will come out. By next week, we should know if this solution will work or if we have to replace the wishbone. I should be able to post another update in a week or two.

[BMWerkeUS]

Update 2:
It has been nearly two weeks since last update. I just checked the ball joint. The flex glue is still intact and there is no sign of a leakage or crack. As far as the noise is concerned, it is completely gone.

[Ryan5034]

Good job on diagnosis. Nice to have articles like this as X5's get older.