Indeed, I saw that also. :confused:
Every seal will fail at some point, only thing is when it fails. :dunno:.

I concur with Dudewanarace. Replacing the vanos seals made a huge difference in my 330xi. The vanos pistons were ridiculously loose when I disasembled them. There was no way it was properly holding pressure. The new seals tightened it up nicely. All the roughness and hesitations disappeared, more responsiveness on the low end, fuel consumption improved from 12.5 l/100km to 10.8 l/100km.

Just because your vanos seals are OK in your experience doesn't mean the problem and the fix isn't real for someone else. The key is to make sure you are fixing the right problem. If replacing the vanos seals doesn't fix your problem it's likely you've misdiagnosed the problem. It doesn't mean the fix is snake oil.

Agreed!

I don't think the seals would be worn out at 20K miles, so true that is probably a bit exaggerated. 120K maybe.. 150K for sure. Lets be clear, this is the M54TU motor I was working on. With the cold idle stumble it would often die. No engine codes, so clearly a problem. I'm not saying everybody needs to do it, but I did and it was awesome. The seals were $60, valve cover gasket set ~$50, Vanos Gasket ~$15.. Worth it.

Ray and Dude, did you replace your X5 vanos seals?

Yes, I did the work myself while I was replacing the valve cover gasket. Instructions from Beisan are excellent. I'm not sure if I would have decided to do just the vanos seals on their own but I was in there anyway doing the valve cover gasket so it was marginally incremental work. I'm glad I did.

The thing about the vanos seal failure is that it's gradual. You'll never just notice it one day, it creeps up on you over months and years. I sure did notice after the fix though. Now I remember how it drove when it was new. Funny thing that snake oil ;)

Word of caution though, it's a fairly involved DIY and while the steps are not complicated there are a lot of steps. Make sure you've eliminated all other potential causes for your engine symptoms before you dive in. I would consider timing the fix to coincide with a valve cover gasket replacement and change of spark plugs since much of the effort is in common.

Ray - thanks for your input! I did not know that i should replace vanos seals when i was working on spark plugs and valve cover gasket replacement. I ordered vanos seals kit already and I have all tools available and ready to do it soon.

It's not that you need to replace the VCG and spark plugs with the vanos seals. It just turns out that the timing for replacement is roughly the same for many vehicles and you can save a lot of effort by doing them together.

I should mention that my VCG was so brittle and aged that it broke into pieces when I removed the VC. So even if yours isn't leaking and you don't plan on replacing it be prepared to get one any way. Really, it's a no brainer since the gasket is cheap compared the to time and effort it takes to remove and replace the VC.

I just finished vanos seals rebuild today. It took ~4.5 hours to complete the entire job. Inner vanos seals rubber cooked and feeling like hard plastic.

^Remember that you need 300mi of city driving to break-in the new seals.

300 miles? that alot, Rajaie told me only 200 miles lol :) When is your turn tmv? :)