[Cebra]

RPM fluctuates when idling. Is this a sign of Vanos solenoids not functioning properly?

https://youtube.com/shorts/ubugMKrIf94?feature=shared

[Three_thirty_I]

Originally Posted by Cebra

RPM fluctuates when idling. Is this a sign of Vanos solenoids not functioning properly?

https://youtube.com/shorts/ubugMKrIf94?feature=shared

If they have never been cleaned, I would definitely give them a clean, then swap them around when refitting. Other things to check in order to determine what is causing the unstable idle is the eccentric shaft sensor plug for traces of oil, either leaking/sweating gasket or the sensor leaking itself, and then a bit more of a job, but inspect/replace the Vanos Check Valves since they might be dirty, MAF sensor could need a clean with some good MAF cleaner. The other thing to check is the part number of the Vanos solenoids, yours will most likely have the older original part, these were replaced a few year later with an updated part which has a different part number. But that being said, my old '05 330i had the original solenoids which I had cleaned a number of times over the years, and never had unstable idle issues, and when I finally replaced them with the newer updated parts, there was actually no change in the way the engine performed and ran, so they were for all intents and purposes still perfect. These are all the basic and easy things to do before digging deeper, and usually solves a niggle like this.

[GoRomeo]

Originally Posted by Three_thirty_I

If they have never been cleaned, I would definitely give them a clean, then swap them around when refitting. Other things to check in order to determine what is causing the unstable idle is the eccentric shaft sensor plug for traces of oil, either leaking/sweating gasket or the sensor leaking itself, and then a bit more of a job, but inspect/replace the Vanos Check Valves since they might be dirty, MAF sensor could need a clean with some good MAF cleaner. The other thing to check is the part number of the Vanos solenoids, yours will most likely have the older original part, these were replaced a few year later with an updated part which has a different part number. But that being said, my old '05 330i had the original solenoids which I had cleaned a number of times over the years, and never had unstable idle issues, and when I finally replaced them with the newer updated parts, there was actually no change in the way the engine performed and ran, so they were for all intents and purposes still perfect. These are all the basic and easy things to do before digging deeper, and usually solves a niggle like this.

Just replace them. Why would you deal with the same issue in the near future? Cleaning them just get you by for a few more months. Also to do the labor twice? IlIm replacing mine in my N52 soon. I still have the original ones. Never had an issue with them after 215k miles. I’ve heard AM ones do the job just fine.

[Three_thirty_I]

Originally Posted by GoRomeo

Just replace them. Why would you deal with the same issue in the near future? Cleaning them just get you by for a few more months. Also to do the labor twice? IlIm replacing mine in my N52 soon. I still have the original ones. Never had an issue with them after 215k miles. I’ve heard AM ones do the job just fine.

Well, that's why I did replace them on my old 330i, was more a case of preventative maintenance and was always wary of the old parts possibly not being 100% despite the car's relatively low mileage for its age at the time. Cleaning them is still a valid exercise in that, it might solve the situation, then you have a good reason to decide whether to replace them now or down the line knowing that the old parts were causing the problem. Changing the solenoids is such an easy job, and that's why I suggested to almost by default replace the check valves, they aren't too expensive, and that's a bit more of a tricky job since they are out of sight where they are located. The ones I fitted were the genuine OEM updated solenoids and also the new OEM check valves at the same time despite the old ones being still spotless (it's not just a filter, so the actual one-way valve could also be a failing).

[StradaRedlands]

Good point on the check valves Three_thirty_I: They are actually a mechanical part that can stop doing the intended job over time.

[Efthreeoh]

Engine idle RPM is not controlled by the VANOS system. The Valvetronic system controls engine idle.

[Efthreeoh]

Originally Posted by GoRomeo

Just replace them. Why would you deal with the same issue in the near future? Cleaning them just get you by for a few more months. Also to do the labor twice? IlIm replacing mine in my N52 soon. I still have the original ones. Never had an issue with them after 215k miles. I’ve heard AM ones do the job just fine.

Apologies for the old man post...

I'm not sure I can actually lay claim to the "clean and swap" of the VANOS solenoids procedure that some of us follow, but waaayyyy back in the day, when I was racking up 35,000 annual miles on my E90, a VANOS code came up at 145,930 miles. The Bently manual says the test procedure is to swap the solenoids with each other to see if the fault code moves with the solenoid or stays with the camshaft (which tells you it is a bad cam position sensor and not the solenoid). That got me to thinking, if the solenoids are the same part for both the intake and exhaust, they must run different profiles for each camshaft position (intake or exhaust). Being the solenoid is an electromechanical device, I figured that each position (intake or exhaust) runs in a set profile of min. and max positions of the valve body. I thought to extend the longevity of the solenoids, why not swap them every so often.

At the time (June 2011) there already was a DIY posted on replacing the solenoids. In that DIY under my previous username Eninty was where I posted it might be a good protocol to clean and swap the solenoids at 50,000-mile intervals. I picked 50,000 miles mainly because it's an easy number to remember and sort of coincides with pulling the intake filter box to replace the airfilter, which gives you more room to work on the solenoids. Up until that point in June 2011 I had not seen where anyone had previously suggested cleaning and permanently swapping the solenoids as preventative maintenance.

I followed my own advice, and my original solenoids lasted for 306,810 miles. At 300,580 miles the 2A87 exhaust cam code came up. I cleaned and swapped the solenoids and replaced the check valves in an effort to cure the code. The check valves were clean as the brand-new ones I replaced them with. The 2A87 reappeared several times in the ensuing three weeks after the new valves when in and the solenoids were cleaned and swapped, so at 306,810 I replaced the solenoids with new OE BMW parts. Given the cost of the solenoids and the 20-minutes it takes to clean and swap them, I think it is worth trying the swap procedure as a first attempt.

OP, if you are going to remove the solenoids to either swap them or replace them follow this procedure:

1. remove both solenoids hold down bolts and place the bolts on your work bench or toolbox away from the engine compartment.

2. Pull the upper solenoid (exhaust) and clean it.

3. Pull the lower solenoid (intake) and clean it and install it in the upper position (exhaust).

4. Install the cleaned exhaust-side solenoid in the lower position (intake).

5. Then bring the hold down bolts back over to the engine bay and adjust the solenoid hold down tabs so the bolt hole lines up with the threaded hole in the head and install the bolts.

That procedure guarantees you will not accidentally drop the hold down bolt into the cam chain box through one of the open solenoid orifices. If you drop a bolt into the cam chain box you are screwed because there is no cam chain cover you can remove to retrieve the bolt.

My 2 cents.

[Three_thirty_I]

Originally Posted by Efthreeoh

Apologies for the old man post...

I'm not sure I can actually lay claim to the "clean and swap" of the VANOS solenoids procedure that some of us follow, but waaayyyy back in the day, when I was racking up 35,000 annual miles on my E90, a VANOS code came up at 145,930 miles. The Bently manual says the test procedure is to swap the solenoids with each other to see if the fault code moves with the solenoid or stays with the camshaft (which tells you it is a bad cam position sensor and not the solenoid). That got me to thinking, if the solenoids are the same part for both the intake and exhaust, they must run different profiles for each camshaft position (intake or exhaust). Being the solenoid is an electromechanical device, I figured that each position (intake or exhaust) runs in a set profile of min. and max positions of the valve body. I thought to extend the longevity of the solenoids, why not swap them every so often.

At the time (June 2011) there already was a DIY posted on replacing the solenoids. In that DIY was where I posted it might be a good protocol to clean and swap the solenoids at 50,000-mile intervals. I picked 50,000 miles mainly because it's an easy number to remember and sort of coincides with pulling the intake filter box to replace the airfilter, which gives you more room to work on the solenoids. Up until that point in June 2011 I had not seen where anyone had previously suggested cleaning and permanently swapping the solenoids as preventative maintenance.

I followed my own advice, and my original solenoids lasted for 306,810 miles. At 300,580 miles the 2A87 exhaust cam code came up. I cleaned and swapped the solenoids and replaced the check valves in an effort to cure the code. The check valves were clean as the brand-new ones I replaced them with. The 2A87 reappeared several times in the ensuing three weeks after the new valves when in and the solenoids were cleaned and swapped, so at 306,810 I replaced the solenoids with new OE BMW parts. Given the cost of the solenoids and the 20-minutes it takes to clean and swap them, I think it is worth trying the swap procedure as a first attempt.

OP, if you are going to remove the solenoids to either swap them or replace them follow this procedure:

1. remove both solenoids hold down bolts and place the bolts on your work bench or toolbox away from the engine compartment.

2. Pull the upper solenoid (exhaust) and clean it.

3. Pull the lower solenoid (intake) and clean it and install it in the upper position (exhaust).

4. Install the cleaned exhaust-side solenoid in the lower position (intake).

5. Then bring the hold down bolts back over to the engine bay and adjust the solenoid hold down tabs so the bolt hole lines up with the threaded hole in the head and install the bolts.

That procedure guarantees you will not accidentally drop the hold down bolt into the cam chain box through one of the open solenoid orifices. If you drop a bolt into the cam chain box you are screwed because there is no cam chain cover you can remove to retrieve the bolt.

My 2 cents.

I also personally believe there is merit to cleaning swapping the solenoids around in order to lengthen their lifespan. Each and every time when I cleaned the solenoids, one was always quite a bit more dirty than the other, can't remember if it was the intake or exhaust located solenoid, but that is then a relevant observation. When removing the solenoids, pay extra care not to have the O-ring and spacer slide off and inevitably fall into oblivion - that happened to me, and had to replace the spacer, discovered it months later sitting inside the cooling fan shroud...

[Efthreeoh]

The VANOS thread.

https://www.e90post.com/forums/showt...olenoid&page=4

[Three_thirty_I]

Originally Posted by Efthreeoh

The VANOS thread.

https://www.e90post.com/forums/showt...olenoid&page=4

I probably read that thread back then, it was also around 2012 when I did various things to my old E90, replaced both DISA actuators, cleaned/swapped solenoids, and a few other things. Leant a lot along the way.