[unixnerd]

So last week I cleaned my N52's VANOS check valves, one was filthy. Got a lot more power between 3-4k miles.

Today my new VANOS solenoid O-rings finally arrived so I've removed and cleaned them. They didn't seem dirty but got a good dose of MAF cleaner anyway (I also cleaned the MAF). I applied 9V to the terminals and they clicked cleanly and opened about 1mm. I'd swear one moves more than the other but hard to tell.

When these die is it a case of total failure or do they degrade over time? I'm chasing a lack of low down power basically. Done a major service and replaced the usual bits but it still seems weaker than it should be under 3500.

[Phil325i]

Rather than replace the solenoids I would first check/clean/replace the VANOS filters. Part No. 11367507729 (you'll need two).

[unixnerd]

Did that last week, one clean one filthy. Good a good bit more oomph. Just had a wee drive after cleaning the solenoids and it's made a small difference. Cleaning the filters really made a big difference.

[Zack_e90]

Originally Posted by unixnerd

So last week I cleaned my N52's VANOS check valves, one was filthy. Got a lot more power between 3-4k miles.

Today my new VANOS solenoid O-rings finally arrived so I've removed and cleaned them. They didn't seem dirty but got a good dose of MAF cleaner anyway (I also cleaned the MAF). I applied 9V to the terminals and they clicked cleanly and opened about 1mm. I'd swear one moves more than the other but hard to tell.

When these die is it a case of total failure or do they degrade over time? I'm chasing a lack of low down power basically. Done a major service and replaced the usual bits but it still seems weaker than it should be under 3500.

The Vanos solenoids do age over time, however, from my experience they seem to age faster when the oil is not changed frequently. Regardless of driving habits ex (hard-driving or tracking) just changes the frequency of oil changes. What happens when you don't change your oil before it becomes more viscous is the oil becomes very thick and mixes with metal shavings/carbon deposits (normal wear and tear) and gets trapped and clogs the solenoids. Just be sure to change your oil filter and oil frequently and you should be fine!

[unixnerd]

Previous owners weren't very good at changing oil, it came out black. Solenoids seem OK since I cleaned them and they click very positively when I apply a battery. I just wondered if there was any point in replacing them. Is the failure mode that they just gum up and die or do they gradually open less with age?