Cracked cam positioning sensor.
 

I have been doing a major overhaul on the top end of my 2006 BMW X5 e53 4.8is. It's been a nightmare by the way, but I won't bore you with those details. I just have a question. As I was taking off one of the valve covers, I slightly cracked one of the cam positioning sensors. It doesn't appear to be a serious crack, and I could probably repair it. Do you think that cracking it damaged it's functionality? I can post pictures later if that would help. It cracked slightly right where the upper cylindrical part of the sensor attaches to the lower square part. It was a small diagonal crack. It appears that it is only plastic that cracked, nothing electrical.

Pictures? It shouldn't affect the sensor right away, you'll know if you get a SES light though. Long term, it will allow dirt/contamination inside the sensor which will degrade its sensabilities. So, plan on replacing it at some point in the future if you don't do it now.

I agree. My mechanic cracked/broke my sensor while doing some other work and he felt it was important enough to replce it which he paid for.

This sensor caused my X to stall when going over a speed bump, or sharp turn at low speed, not mentioning the fear of not knowing when the car will stall again.

Once I changed it, symptoms all gone! So I would say this is a safety critical part. Change it!

I'll take a photo when I get a chance. I'd really rather not replace it as it costs $300, and I'm already in deep on this overhaul. If there is any way to save it, I'd like to.

how about this? considering the dual VANOS system on your engine, along with the Valvetronic, all depending on knowing the exact position of the cam for timing, if the reading isn't reliable, your engine goes into failsafe mode, or won't start. You can try getting everything back together and testing to see how it runs/if it runs. If it does, you could *theoretically* seal the crack with an epoxy or RTV to keep it from getting dirty inside or cracking more. RTV might be the best bet...but, I would be prepared for needing to replace it.

I think I may try that. As big of a pain in the butt as it will be to get the valve covers back off again, it's better than spending $300 on a new sensor. It really looks like it's just the plastic that is broken, I do not see any wires or circuitry get damaged. I may repair the plastic before I reinstall it.

Must be a considerably different R&R on the 4.8, as the sensor on my '01 3.0 is about a 5 min wiggle in/out, and the top of the line version is ~$150, most for around $100.

Yes, I would replace it as others have noted.
GL, mD

Here is the photo.
https://plus.google.com/u/0/104640325132930366002/posts

I hope you can all see that. Why doesn't this forum allow you to upload photos directly to it?