I finally did this job on Monday. So far the cold idle jolts are gone. I feel like I have gained a little low rpm torque but can't say for sure. I changed spark plugs and vcg.
For a beginner like me I would rate the job 5/10. Not that hard but it takes time when you want to make sure you do everything right. Beisan instructions where definitely a must have, of course. Took me about 8 hours.
I have a question though: before the repair, my car would have a jolting idle when warming up, and would sometime hesitate when giving gas at lower rpms (taking off in 2nd gear for instance). Also, it once had a misfire on cylinder 5 after not using the car for more than a week. Clearing the code got the cylinder to fire again and it never happened again.
Now, after the seals replacement, idle is fine but the car still hesitates at lower rpm. And today coming back from work cylinder 5 misfired again (first time it ever starts misfiring when driving). I cleared codes and it runs fine. I thought well maybe I should reset adaptation values so that it starts from scratch with a fresh vanos. I reset them tonight and will report back.
If the misfire happens again I will swap the coil with another cylinder. Then maybe compression and leak down tests if need be. Intake has no leaks, boots are 2 years old, icv and disa are clean, air filter is new. Did a sea foam treatment two month ago (intake fuel and crank case) and changed the oil afterwards. It did improve idle but vanos was still to be done. Exhaust cps is new. I only use castrol LL-01 5w40.
If anyone has an idea please chime in!
Sorry if this post doesn't make sense. I am writing on a cell phone.