Replacing VANOS solenoid valves woke up my N62!
 

I'm not entirely sure what the VANOS solenoid valves do exactly...but I replaced all 4 on my 4.8is N62 as part of some recent upgrades (also did new NGK Iridium IX plugs, ignition coils and serpentine belt earlier in the day).

To my surprise the new VANOS solenoids had an awesome improvement to my engine responsiveness. Best way to describe it is that it's SOOO much more smooth now.

Previously I had a lag or delay after giving it gas (either light or WOT). After applying throttle it would just think about it for a second but then suddenly kick it and jerk your head. Now it's accelerating evenly and more quickly like I always expected it to. Seems more "peppy" on the butt dyno.

Am I going crazy? :dunno:

Why did you replace them? Mileage? Maintenance?

Also, did you go with an OE BMW replacement or aftermarket?

Replaced as part of troubleshooting a strange vibration after valve cover and upper timing case cover gasket replacement job. Thought they might of gotten damaged somehow. I was taking shots in the dark and replaced plugs, coils and vanos trying to find a solution. Turned out to be something totally unrelated. Decided just to keep them anyways.

I'm at 79k miles. Went with some knocks offs from Amazon. 1 of the 4 I got was a dud (threw misfire codes on that entire bank). But exchanges are always easy with Amazon so not the end of the world. Replacement one was fine.

Are you sure it's not the coils or the plugs that blessed you?:D

Fairly confident. Had replaced those earlier in the day while trying to diagnose the original issue. I had test driven around town a bit to test and did not notice anything different at that time.

As soon as the new VANOS went in and I test drove it is when I first noticed the difference.

Here's a good article I've come across in the meantime on what/how it helps/when to replace: https://www.bmwn54tuners.com/diagnos...-vanos-system/

Vanos controls the difference between intake and exhaust camshafts. The exhaust camshafts are locked in phase with the crank shaft but the intake camshafts will vary to change how long they are open and when they open. On the N62 in addition there is an additional set of hardware that amazingly also changes how FAR they open!

The solinoids control the vanos and if it's sticky it will most certainly affect throttle performance at any position. It's about 30 hours less work to change the solinoids vs refresh the vanos seals so very good news for you.

On my M54 with Double VANOS, the exhaust camshaft does get adjusted relative to the crankshaft. It was the single VANOS that only adjusted the intake camshaft. And with double VANOS, it can be continously adjusted. Pretty cool. Amazing, actually.

I just rebuilt (seals and rattle rings) the double VANOS on my '01 3.0i. I did not touch the solenoids, not even to replace the o-rings that were supplied in the Victor Reinz head gasket kit, figuring they were easily accessible if they were to ever cause a problem, and I thought there was a chance I might actually create a leak by touching it.

As you say, though, replacing the internal VANOS seals and rattle rings is usually a much deeper dive. But in my case, it was easy since I had the head off already.

Interesting link - thanks.

I've got to say though, time and time again this car amazes me. It's at 186k miles, and every time I open something up I find it to be in excellent shape. I don't think my VANOS system had ever been touched, and I replaced the seals and rattle rings mainly because I was right there and everybody says they need to be refreshed (e.g., that page says at 70k miles). I did it, but am not expecting an improvement.

Similar data point for longevity - The starter is not easy to get to, so I figure this would be a good time to inspect and put in new brushes. I did that, but the old 186k mile brushes still had 70% left (but you can't really take them down to zero, so ...). I replaced with new anyway, of course since I was in there, cleaned out all the carbon powder, greased things, etc.

Rebuilt alternator too. Similar findings. Built to last.

Now the doors and window regulators ... on the other hand ...

Replacing VANOS solenoid valves woke up my N62!
 

I didn't realize M54 had dual vanos. Does help explain how the little engine that could does what it does. I also have M54. Of course the m62 also has dual Vanos is just one for Bank

School me...how does the solenoid work exactly? Guessing it gets input from the wiring harness on the front (the part that sticks out)...but oil runs through the other end that is inside? For what purpose...like what does the solenoid do specifically to make all this fancy VVT function.