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Big Will

noise from cruise control actuator

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Hello all,

As I continue my quest to get this 525iX touring completely sorted, I'm currently working on solving a strange noise that I first noticed when I drove the car from the dealer back home. At the time, my priority was solving the no-start condition that the car developed on the trip back across Germany (a dead DME). At Autobahn speed (130+ kph) a very strange almost grinding noise would occur from what seemed like directly behind the instrument cluster. It was so constant and didn't really change in pitch but always started around the same speed and was so loud that it would completely drown out the radio! I've attached a video so you can get a sense.

 

While the car was at BMW initially for the starting problem, I mentioned this and they said it was the noisy water valve. This made no sense and of course wasn't the problem. I removed the instrument cluster assuming it would be some broken clips or wires from the harness rubbing on something but driving the car without the cluster made no difference (at least I took the opportunity to change all 23 bulbs) and the cluster itself was in good shape.

 

BMW then gave a shot at test driving it and decided that it was the cruise control cable in the engine bay whacking up against the strut tower because a cable mount was missing. We installed the missing cable mount (12511268352). This did not fix the problem. I continued to trouble shoot until almost by accident I tapped on the cruise control actuator. It was the exact same sound but much quieter (see video attached). I noticed that the 3 nuts mounting the actuator to the bracket were also loose probably from vibration. I replaced the two rubber grommets (37211119643) that dampen the attachment of the bracket to the SLS reservoir in the hope that new rubber would dampen the vibration and then replaced the 3 nuts that attach the actuator to the bracket studs and added some loctite. After a lot of driving, re-positioning the bracket, and re-tightening, the problem is solved. There is literally one orientation of the bracket that seems to keep the vibration to a minimum. However, I know that anytime I have to remove the actuator for any other repair, it will be a lot of effort to get it back into the one position that doesn't vibrate and cause the horrendous noise.

 

I also opened up the actuator and noticed that indeed the noise is coming from inside the actuator itself. You can hear it by tapping on the case. Has anyone ever had anything like this before? Is there a solution other than buying a new actuator or hoping a used one won't have the issue?

IMG_3466.thumb.JPG.817c66bcdb4d16e98868433a274b1139.JPG

Also, I ordered a new mounting bracket but the one that arrived doesn't work for the iX because there's a little fuse box that needs to be attached to the bracket and the BMW part no longer seems to have the shoulder to mount it. Does anyone know what the correct part number is for the iX bracket? The number I used was      65711384767. You can see the iX bracket below with the shoulder for the plastic clip to attach the little fuse box.

 

IMG_3465.thumb.JPG.30b2cb1da2103dcf80043474fe065a5a.JPG

 

Thanks for any guidance as always!

 

525iX_noise_edited.m4v

525iX_noise_cruisecontrol_actuator.mp4

Edited by Big Will

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I wanted to update this post as I've finally solved this annoying mystery.

 

It turned out that the crazy noise heard in the attached videos above wasn't actually the clevis vibrating inside the cruise control actuator. Despite the fact that tapping on the actuator produces a similar (albeit quieter) version of the sound heard in the cabin, after trying two used actuators and replacing the cruise control cable itself, the noise was still there. For a while, I thought that adjusting the angle that the actuator sat at made a difference but it turned out just to be coincidence and probably had to do with the way the wind was hitting the car at a given moment.

 

On a very late night drive last weekend coming off of a ferry, the noise was driving me nuts so I pulled over and with a flashlight tried to trace how a noise from the actuator would translate into the cabin and it didn't make sense. By accident, my hand tapped the plastic cowl that covers the wiper actuator and eureka! The two-piece cowl had quite a bit of play in it toward the center on both the driver and passenger piece. This was what was making the noise! When wind would hit the cowl it would cause the plastic to tap against the metal of the body at the edge of the engine bay below the windshield.

I taped the pieces in place and the noise was gone.

 

The fix was to replace the old plastic rivets as some of them had broken over the years. There are 8 of them in total and the part number is 51711928946

 

When you replace them it's a good idea to take the opportunity to remove the cowl pieces and clean under there and this also gives you the chance to ensure that the two pieces are placed back together correctly to minimize any chance for vibration to occur. To do this, you pop out the old rivets, remove the two 13mm nuts holding the wiper arms in place (be careful not to lose the washers underneath) and then lift arms off. If you have the wiper arms that are automatically pressure adjusting I believe there are a pair of allen head screws instead of 13mm nuts. Once the wiper arms are out of the way, the cowl pieces will then lift up and out.

 

 

Edited by Big Will

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