Vanos Solenoid cleaning

[NB92325]

Hi guys

Just wondering whether it's worth cleaning the vanos solenoids (N52B25) and giving them fresh seals just as a routine "might as well since the seals are cheap and the job looks easy even for me)? Car has 160k on the clock but is not showing any typical Vanos-related issues, other than I had a bit of a jumpy rev a few mornings ago but it went away after like 5 seconds.

I know the check-valves are also an obvious job, but I don't have the tools to make access to them do-able and for the price of a trolley jack and the other tools I may as well ask my mechanic to do it when he services it at 165k.

But on the Vanos solenoids - is it more a leave it in peace item or worth cleaning?

Cheers!

 

[Kyle]

Definitely worth cleaning then, I just stuck the ones from my N54 in a jar of petrol to 10 minutes.... There are some more complicated cleaning methods but I found this worked just fine.

the check valves aren't that complicated to remove, no need to remove the wheel etc... I did mine from the top with a normal torx driver.

 

[DarrylvanNiekerk]

After a bit of research online I got a can of brake cleaner and sprayed through all the little holes and into the back section shaking them out until the fluid came clean and I could hear the solenoids moving freely.

I tested their action with a 9v battery to check they were clicking properly and then reinstalled.

When you pull them check the metal grates for any filings or build up to get an idea of engine health.

 

[NB92325]

After a bit of research online I got a can of brake cleaner and sprayed through all the little holes and into the back section shaking them out until the fluid came clean and I could hear the solenoids moving freely.

I tested their action with a 9v battery to check they were clicking properly and then reinstalled.

When you pull them check the metal grates for any filings or build up to get an idea of engine health.

Thanks, yeah I saw that method too. Reckon I'll first order a set of solenoid seals from the dealer at least so that I can replace them after cleaning.

As for the check-valves I see if I can figure it out from the top with a mirror. Really not keen on the wheel well route.

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[DarrylvanNiekerk]

Thanks, yeah I saw that method too. Reckon I'll first order a set of solenoid seals from the dealer at least so that I can replace them after cleaning.

As for the check-valves I see if I can figure it out from the top with a mirror. Really not keen on the wheel well route.

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Yeah, you don't want to pull those solenoids without changing the gaskets. I did that and had a massively oily engine to clean afterwards. Definitely buy from BMW, they are cheap and it is not worth the hassle using non OEM.

 

[NB92325]

So I did the job yesterday. Took out the solenoids, cleaned as good as I could with Carb Cleaner and microfibre and replaced the seals with OEM set.

Few things that bother me:

- The car has 160k on the odo and I am certain the solenoids have never been out, but I was surprised at how much dust / light grit was on the seals when removed. I suppose that's what they're there for but still a surprise (and no it wasn't shavings- just light dust).

- some videos have stated the solenoids should make a sound when shaken (others activate them with 9v batteries, but I didn't do that). Mine made no shaking noise, but surely if they were kaput the car would throw codes and even stall at idle I've read?

Regardless, I still suspect that the check-valves need a good cleaning as the jumpy revs at cold-start remain even after the job. I just don't have the balls to try and do the valves from the top of the engine and don't have the tools for the wheel access option so probably going to just have it done with next oil change in 3k.

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[NB92325]

Well perhaps I was too quick to post - did the job on Saturday and left the car till this morning for my commute to work and the cold start was perfect. No jumpy revs - just straight to about 900 revs and smooth idle. So maybe it just needed more time for the carb cleaner to do its thing.

Probably also placebo effect, but the car certainly felt like a better drive today.

 

[NB92325]

So I borrowed some tools from a neighbor and decided screw it. Tackled the vanos check valve job from the top and must say, yes it's awkward bit with the coolant expansion tank moved out of the way it's not bad at all.

But look at this!!!!

Carb cleaner did the job and I reinstalled. Smooth idle from the get go.

Cannot recommend the job enough on higher mileage e90s!!!

Man what a rewarding exercise!

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[GHOST E90]

Well done man
Care to share the steps you followed ?

 

[NB92325]

Well done man
Care to share the steps you followed ?

Sure - tools you need is a quarter drive and a 10mm socket (for removal of expansion tank bolts) and a T40 bit for the valves themselves.

First I removed the expansion tank bolts and the electric connector at the bottom of the tank, moving it with its pipes still connected to the right (facing the engine from the driver front wheel) as far as I can. This was helpful for getting hands on the valves once loosened and also to get a view with my phone camera because most of the job is blind from the top.

Then, the valves are basically tucked under and to the right of the exhaust manifold (careful, even with a very short drive that thing is red hot).

The pictures will give you an idea what to look for - basically access is between those wires and the (I think) AC line which is covered in what looks like foil haha.

I took an extension and the T40 bit and first seated the bit, then attached the driver and loosened it (anticlockwise). It needs a bit of unscrewing and then you wiggle them loose. A few drops of oil will come out but there's nothing which the oil can't fall on - it burns off (with the solenoids though it's critical not to mess oil on your belts as it can be catastrophic- as in belt in the engine catastrophic).

I then catch the valve with my hand and that's it - clean with carb cleaner, wipe off with microfiber, lube the seals and then reinstall.

Torque is apparently 15nm but I just tightened till they bottom out as I don't have a torque wrench but you'll know when it's right.

Then just clean what you can in the area and reinstall coolant expansion tank (remember that electrical connector!) and you're done.

Then enjoy a cold beverage!

Good luck!

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[NB92325]

Oh, BTW the pictures posted are mid removal, hence the bit of oil there. When installed the valves are about 2mm deep recessed in their holes - not flush or protruding.

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[DarrylvanNiekerk]

So I borrowed some tools from a neighbor and decided screw it. Tackled the vanos check valve job from the top and must say, yes it's awkward bit with the coolant expansion tank moved out of the way it's not bad at all.

But look at this!!!!

Carb cleaner did the job and I reinstalled. Smooth idle from the get go.

Cannot recommend the job enough on higher mileage e90s!!!

Man what a rewarding exercise!

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Did you check the action of the valve after cleaning?

It is a very basic system with a spring and a small ball bearing that allows oil to flow in one direction under pressure and then stops oil from flowing in the reverse direction so you don't need to build oil pressure and flow every time you start the car.

I pushed the bearing down and sprayed cleaner through the entire valve to make sure they were spotless inside and out before reinstalling.

That is some significant sludge build up there, might be an idea to do an engine flush at your next oil change.

 

[NB92325]

Did you check the action of the valve after cleaning?

It is a very basic system with a spring and a small ball bearing that allows oil to flow in one direction under pressure and then stops oil from flowing in the reverse direction so you don't need to build oil pressure and flow every time you start the car.

I pushed the bearing down and sprayed cleaner through the entire valve to make sure they were spotless inside and out before reinstalling.

That is some significant sludge build up there, might be an idea to do an engine flush at your next oil change.

I sprayed carb cleaner through the mesh and then shook it out though the valve. Eventually you could hear the bearing move around again and no more dirty oil came out so I figured it's clean enough. Now that I know how to do it I'll probably do it again after a few k to check for improvements.

The sludge was hectic but I reckon that's the first time in 160k that they've been cleaned and based on videos I've watched it's perfectly normal for these high mileage valves.

Thanks for the feedback!

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