[e92countryboy]

Hi guys,

Title summarises the issue nicely. My car is a 2006 E92 325i with the 2.5 N52 (Euro spec, UK) at 148k miles. When the car is started cold, I have no funny issues, car has normal power, all is well. If the car is stopped and restarted once the oil reaches around 80 degrees Celsius (176 deg F), the car surges from around 600-700 RPM, up to about 1400, then drops down. Here's a video. Following this, 100% of the time, the car will be utterly gutless below 3500 RPM and lacks power through the rest of the RPM range too.

If you start it while warm a few (2 or 3) times consecutively, it will eventually illuminate the CEL just after surging. I have a Foxwell NT530 which shows the only code to be the infamous 2A82 VANOS intake code. But again, it only does this when started warm. Cold starts are perfect. I wouldn't be too worried about this if it wasn't for my MOT next month. I'm worried that after the garage take it on and off the ramp a few times during the test, the CEL will illuminate and cause it to fail.

Here's a list of work I've done since August last year, when I got the car:
• Brand new genuine VANOS solenoids
• Swapped solenoids, code remains on intake side
• Removed and cleaned VANOS check valves (not replaced)
• Oil and filter flush and change, replaced with Castrol Edge 5W-30 LL (should be approved, but has apparently lost certification, topping up with M variant now)
• Replaced oil filter cap, old one was missing filter cage and VANOS O-ring. Performance improved enormously from this
• Big DISA valve replaced, motor had failed. Small DISA not touched yet, but seems to be working
• Various adaptation resets and relearn procedures, VANOS, Valvetronic, etc
• CCV diaphragm replaced (built into plastic VC, rest of VC untouched)
• Checked ESS connector, no oil in connector or around pins

The oil change was done around 4.5k miles ago, so I'm thinking I will change it again for good measure before the MOT anyway. My suspicion is that it's related to the oil viscosity when warm, but I'm not confident.

I want to do plugs, but I figured this issue is unrelated to plugs seeing as I've actually got a VANOS code. One thing at a time haha

Any help would be much appreciated. I feel like I've ticked off most of the common failure points for VANOS faults, and the warm start thing leads me to believe it's related to the oil viscosity when hot, but I'm hoping someone else knows better. Cheers

 

[gbalthrop]

... 2006 E92 325i with the 2.5 N52 (Euro spec, UK) at 148k miles. When the car is started cold, I have no funny issues, car has normal power, all is well. If the car is stopped and restarted once the oil reaches around 80 degrees Celsius (176 deg F), the car surges from around 600-700 RPM, up to about 1400, then drops down... only code to be the infamous 2A82 VANOS intake code.
• Replaced oil filter cap, old one was missing filter cage and VANOS O-ring. Performance improved enormously from this...
The oil change was done around 4.5k miles ago, so I'm thinking I will change it again for good measure before the MOT anyway. My suspicion is that it's related to the oil viscosity when warm, but I'm not confident. [Certainly FIRST Suspect! Oil PRESSURE is needed to properly Advance Cam timing at idle, and Hot, LESS-Viscous Oil has lowest pressure at idle. See Below.]...

Replacing missing "cage" on which filter element is mounted, and also small O-ring, "greatly improved" performance. That was due to improved oil pressure, particularly at idle. Your 2A82 code ONLY on hot start idle MAY be due to low oil pressure due to collapsed filter element.

When engine is COLD, I would remove the Oil Filter Housing Cover, slowly lift the Cover, allowing oil to drain into Filter Housing from filter element, and then examine the filter element. Also check to see that "Cage" is attached to Cover, Element is on Cage, and small o-ring is intact.

If you have INPA/ISTA, or a Scan Tool that can display Live Data of Cam Angle, Actual and Target, you can monitor what is actually happening, which would help identify Cam Position Sensor Signal as received by DME, AND VANOS Solenoid function and VANOS Unit response.
George

 

[e92countryboy]

Replacing missing "cage" on which filter element is mounted, and also small O-ring, "greatly improved" performance. That was due to improved oil pressure, particularly at idle. Your 2A82 code ONLY on hot start idle MAY be due to low oil pressure due to collapsed filter element.

When engine is COLD, I would remove the Oil Filter Housing Cover, slowly lift the Cover, allowing oil to drain into Filter Housing from filter element, and then examine the filter element. Also check to see that "Cage" is attached to Cover, Element is on Cage, and small o-ring is intact.

If you have INPA/ISTA, or a Scan Tool that can display Live Data of Cam Angle, Actual and Target, you can monitor what is actually happening, which would help identify Cam Position Sensor Signal as received by DME, AND VANOS Solenoid function and VANOS Unit response.
George

Hey George,

Thanks for your fast response. Of course, I was thinking about the viscosity but didn't consider how that would affect the pressure. What you're saying makes sense. The current filter is direct from the local dealership so not a poor quality one. I replaced the filter cap maybe 3k miles after that filter went in, but I didn't notice that it looked damaged or collapsed when I did so. The previous filter went around 7k with no "cage" and was fine when it came out. Definitely worth a look tomorrow, although it won't be until tomorrow evening after work that I'll be able to check.

I believe the Foxwell unit I have can check target/actual cam angles. Using that data, will I be able to narrow down the problem area? If I can, I'll try to plot RPM too, might give more insight into how the oil pressure is affecting it.

For high mileage engines, is it preferable to go with a thicker oil to maintain VANOS? I would normally just replace with more 5W-30, but maybe it's worth going up to 5W-40.

Cheers!

 

[e92countryboy]

Update - checked the oil filter yesterday (Saturday) but didn't get time to make a post. The oil filter, to my eyes, looks perfectly fine and completely intact. The fins are not bent, clogged or misshapen. The element in the center of the filter cap is still attached, as is the O-ring.

The only odd thing I noticed while doing this was that when I first opened the filter cap and removed the filter, there was a massive amount of oil still in the housing. The engine had been turned off for around 2 hours by this time and was still very hot in places, but I was working in direct sunlight so I think it was due to that rather than residual heat from the engine. The oil in the filter housing drained as soon as I removed the filter, but it was almost filled to the top of the filter housing, where the threads are. I don't know if this is normal or not.

I've attached a few images that I took. I noticed the element in the center of the cap has a spring, and also that the center nipple with the O-ring on it has no hole in it. I was expecting to see a hole to direct oil to the smaller exit at the bottom of the filter housing, but this doesn't seem to be the case. Is there a mechanical function to the filter cap? Weird stuff!

I've ordered the bits for a full oil and filter change so I'll be doing that later this week, possibly next weekend.

 

[e92countryboy]

So, I made a new observation today. As stated in my OP, I replaced just the CCV diaphragm in the valve cover a few months back. I did not replace the whole VC, just the rubber diaphragm towards the back of it. Cracked the old one and pulled all the bits out, glued the new one in with silicone. Didn't seem to make much difference, at the time the oil filler cap on the VC would pull a small vacuum while running, but it didn't seem excessive and I could still open the filler cap.

In the last week or two, I've been getting a funny squealing noise from the front of the engine. I didn't mention this in my OP because I assumed it was just a bad belt or alternator on the way out and I wouldn't need to worry about it for a while. Well, I checked the oil filler cap again today and it could have been glued down for how hard it was to open, enormous vacuum and the engine was trying hard to avoid stalling when it was opened. So, vacuum leak from CCV I guess. The squealing went away, so must be whistling through the filler cap.

This post here says that vacuum leaks "can and will" cause VANOS codes, among all the other issues with vacuum leaks. So I guess that's where I have to look now.

I really want to avoid the £350 brand new VC from the dealership if I can, but I know cheap ones have a tendency to not seal or work properly. I don't know if this is definitely the VC or the oil separator, if the UK spec 325i even has one. Is anyone able to point me in the right direction for troubleshooting or finding cheaper parts to solve this issue? Would appreciate any pointers. Cheers

 

[Watchme]

While many people replaced just the diaphragm in the valve cover without issues, there are many nuances to the process as well as part selection. I did a bit of research and in the end just replaced the whole valve cover (oem from FCP). If you look around, there's an article somewhere that explains how to measure / modify the aftermarket diaphragm and spring to get a closer match to stock. Also point out a few detailed items to pay attention to. The valve uses the flex of the rubber material and the spring rate to fine-tune the vacuum in the crankcase, so it shouldn't be a surprise some aftermarket parts work better than others.
If you have too much vacuum, the diaphragm is simply stuck-open or nearly so allowing unrestricted connection between the IM and VC space. So basically, you are getting full intake vacuum, or close to it.
I would first make sure you don't have a separate unit for the oil separation (PCV, CCV, whatever). Enter your car and drill down to components. www.realoem.com

 

[dukedkt442]

You have what looks like red RTV or loctite on the edge of the cage and filter; if that garbage has been circulating through the engine, oil circuit may be compromised. It’s a little bit of a PIA on this engine, but oil pressure readings when hot can tell you a lot. I know of engines that have seized due to extra copious or incorrect applications of sealant.

Remove the check valves/screens upstream of the VANOS solenoids and check them for sludge/debris/RTV.


Via the interwebs

 

[e92countryboy]

While many people replaced just the diaphragm in the valve cover without issues, there are many nuances to the process as well as part selection. I did a bit of research and in the end just replaced the whole valve cover (oem from FCP). If you look around, there's an article somewhere that explains how to measure / modify the aftermarket diaphragm and spring to get a closer match to stock. Also point out a few detailed items to pay attention to. The valve uses the flex of the rubber material and the spring rate to fine-tune the vacuum in the crankcase, so it shouldn't be a surprise some aftermarket parts work better than others.
If you have too much vacuum, the diaphragm is simply stuck-open or nearly so allowing unrestricted connection between the IM and VC space. So basically, you are getting full intake vacuum, or close to it.
I would first make sure you don't have a separate unit for the oil separation (PCV, CCV, whatever). Enter your car and drill down to components. www.realoem.com

That's what I was worried to hear, seems the cheapest place to source a new VC at the moment, weirdly, is direct from my local BMW dealership for around £350. I will have a look for that article and I'm tempted to try replacing it one more time to be sure that it can't be fixed on the cheap - the diaphragms are only around £20. Good to know about the flex of the rubber and spring rate, I will try a different supplier if I try it again.

I've seen others testing the diaphragm by gently blowing or sucking air over the diaphragm using a tube attached to the nipple on the cap. I will give that a go too once I get the car back later. Thanks for the tip about realoem, what a site! Every part and bolt of every section of the engine. Brilliant. Looks like I only have a "vent hose" on my engine but I will double check the exact production date later to make sure I have the right datasheet.

This thread from 2016 gives a lot of info about how the CCV works in engines without the external cyclonic oil separator that is so often shown when discussing CCV. If this is accurate for my engine, and given your explanation, I'm hoping the diaphragm is the only part that could cause this type of failure. Gives me a bit more hope that this issue can be sorted without extreme cost. Thanks a lot for your comment, much appreciated

 

[e92countryboy]

You have what looks like red RTV or loctite on the edge of the cage and filter; if that garbage has been circulating through the engine, oil circuit may be compromised. It’s a little bit of a PIA on this engine, but oil pressure readings when hot can tell you a lot. I know of engines that have seized due to extra copious or incorrect applications of sealant.

Remove the check valves/screens upstream of the VANOS solenoids and check them for sludge/debris/RTV.


Via the interwebs

Whereabouts on the filter cap are you referencing here? This particular cap is brand new (less than 1k miles) direct from the local BMW dealership, filter from the same place with around 5k. I fitted it myself and didn't use any sealant at all when fitting, just torqued to spec at best as I could.

The VANOS check valves were removed, checked and cleaned this time last month, a bit of what I suspect was metal shavings that just wiped off, but they were not completely blocked like some I've seen and cleaning them didn't make much difference in general. I've attached an image of the worst one, the other barely had anything.

Do you happen to know what purpose the spring serves at the top of the filter cap? Looks like it should do something, maybe open the hole at the bottom of the filter housing? But the cage doesn't seem to move at all.

 

[dukedkt442]

Look on your cap, and also on your filter. Your pictures show red clear as day, unless just a photographic effect.

That sludge on your screens is highly disconcerting! I can pull mine out tomorrow at 190k miles and they’ll look like they just came out of the box. Metal in the sludge is abnormal, and a product of some areas not receiving proper lubrication. Did you remove and swap the solenoids too, along with cleaning them and bench-testing them with a 9v battery?

Your issues are largely oil-pressure-related, due to the amount of sludge in the oil galleys. If you pulled the cam cover, you’d likely see more, or at least looked down through the oil cap with a scope. I’d definitely get oil pressure readings. VANOS is driven by oil pressure and won’t function properly without a proper pressure signal.

I personally would not mess around with anything without sussing the sludge issue. Since you’re due for an oil change (at 4500 miles, you’re due), send in a sample to Blackstone. That will tell you more.


Via the interwebs

 

[e92countryboy]

Look on your cap, and also on your filter. Your pictures show red clear as day, unless just a photographic effect.

That sludge on your screens is highly disconcerting! I can pull mine out tomorrow at 190k miles and they’ll look like they just came out of the box. Metal in the sludge is abnormal, and a product of some areas not receiving proper lubrication. Did you remove and swap the solenoids too, along with cleaning them and bench-testing them with a 9v battery?

Your issues are largely oil-pressure-related, due to the amount of sludge in the oil galleys. If you pulled the cam cover, you’d likely see more, or at least looked down through the oil cap with a scope. I’d definitely get oil pressure readings. VANOS is driven by oil pressure and won’t function properly without a proper pressure signal.

I personally would not mess around with anything without sussing the sludge issue. Since you’re due for an oil change (at 4500 miles, you’re due), send in a sample to Blackstone. That will tell you more.


Via the interwebs

Ah, I see what you mean but I didn't consider that anything to be concerned about. I believe the now-red bit was yellow when the filter was new, so probably just the way the colours are clashing. If you look at a part that used to be white, like the fins, it's the kind of colour you'd expect.

In general, I don't think sludge buildup in my engine is that bad. The cams, when viewed from the oil filler flap, could look better but it's not game-ending sludge. According to the service history book, this engine has suffered BMWs long OCI though, sometimes up to 15k in the earlier years of it's life. It's in better hands now. Don't forget this engine is 16 years old, has traveled 150 thousand miles and has had 4 other owners before me. Metal in a filter than is not cleaned as a part of an official service procedure doesn't seem out of the ordinary. I can only try to stop further wear.

I didn't bother cleaning the old solenoids and just replaced with brand new OEM straight from BMW after they failed on a road trip. When this recent issue popped up, I swapped them to rule them out and the code remained on the intake side. The new solenoids only have around 7k on them I reckon.

At the last oil change, I ran a bottle of engine flush through before dropping the oil and refilled with the oil mentioned in the OP. I will try to get a hold of a stronger flush before this oil change to clear out what I can. Unfortunately I'm UK based so Blackstone is no good for me, but I may grab a sample to send to one of their UK counterparts. Not sure how engine flush would affect the results though.

Do you entirely discard the theory that bad CCV and excessive crankcase vacuum would cause VANOS issues, as the poster in the linked thread suggests? Seems I should try to get my CCV sorted too. Cheers for your help

 

[Watchme]

I won't claim a definitive solution, just a few more insights. For all we know, you may be digging into a can of worms. But my usual instinct with cars, is to fix known issues; later address what "may" be broken.
So, I would first fix your CCV. Excessive vacuum is bad for idle. If you want to measure your crankcase vacuum just to be sure, look into my thread here N51 Idle Stumble - MAF Sensor, CCV, Fuel P? (Not Fixed) I used a tool there. Vacuum should be around 33 mbar or so. If you have 50, then CCV is shot.
Another simple check is to open the connector to the eccentric shaft sensor and see if there's oil in it. See if there's any oil around the sensor at all.
Not sure how much sludge is too much. Just like dukedkt442 my non-return valves looked brand new at 155k miles, but I replaced them anyway. He's right that the only way to tell if you have healthy oil flow is to measure the pressure. Not sure how it's done on our engines, might have to look around Engine Oil Pressure Test Kit
Speaking of oil, I think the red in your photos is a camera effect. The basket for filter housing "looks" ok. Maybe you can look at it with a bit more detail, reference post 19 here 2A82 Vanos Inlet Code The spring you are asking about is the bypass valve: when filter element has too much pressure drop, the valve will open allowing unfiltered oil to flow through.

 

[e92countryboy]

I won't claim a definitive solution, just a few more insights. For all we know, you may be digging into a can of worms. But my usual instinct with cars, is to fix known issues; later address what "may" be broken.
So, I would first fix your CCV. Excessive vacuum is bad for idle. If you want to measure your crankcase vacuum just to be sure, look into my thread here N51 Idle Stumble - MAF Sensor, CCV, Fuel P? (Not Fixed) I used a tool there. Vacuum should be around 33 mbar or so. If you have 50, then CCV is shot.
Another simple check is to open the connector to the eccentric shaft sensor and see if there's oil in it. See if there's any oil around the sensor at all.
Not sure how much sludge is too much. Just like dukedkt442 my non-return valves looked brand new at 155k miles, but I replaced them anyway. He's right that the only way to tell if you have healthy oil flow is to measure the pressure. Not sure how it's done on our engines, might have to look around Engine Oil Pressure Test Kit
Speaking of oil, I think the red in your photos is a camera effect. The basket for filter housing "looks" ok. Maybe you can look at it with a bit more detail, reference post 19 here 2A82 Vanos Inlet Code The spring you are asking about is the bypass valve: when filter element has too much pressure drop, the valve will open allowing unfiltered oil to flow through.

Oh, it's always a can of worms when it comes to working on the N52! And yes that's good advice, I should have learnt that when I had "engine troubles" caused by a bad wheelspeed sensor a few months back.

Thanks for sharing your thread, a lot of useful info about the CCV there. I know you're in the States, but roughly how much did you pay for the new VC? £350 seems excessive to fix a fault which seems to be caused by just a little rubber flap. To be honest, I don't think I even need to actually test the crankcase vacuum - it is at times strong enough to hold the oil filler cap down. Really struggle to open it when it's acting up. Pretty damning evidence IMO.

The ESS connector is good thankfully. Checked it a few months back when I was having other issues, no oil or dirt or anything, so don't think that's the issue.

Odd about the check valves. I assumed that level of particulate and dirt was usual. To be clear, it was more like wet sand in consistency than "sludge" or mud, particles suspended in oil. It just wiped straight off with a paper towel and I blew the remaining metal particles out with aerosol engine cleaner. I will see about getting an oil pressure test done, although I will have all the parts by the end of the week to do a full flush and change anyway. Something for this weekend.

Thanks also for that e90post thread and linked video. The SIB in the description is particularly interesting where they mention that a lack of filter element will cause unfiltered oil to be supplied to the VANOS system. Might well be why my check valves are nasty, because that bit was missing for at least 7k before my first oil change and possibly even before that! That's a lot of unfiltered oil.

I've got a lot of bits to look at here, I really appreciate the input from both you and dukedkt442. I'm collecting the bits for an oil change tomorrow, including a LiquiMoly engine flush and CeraTec oil additive for the new oil. I'll get that done probably Saturday afternoon if not before and go from there. I'm quite certain I'm going to need something for the CCV too. Thankfully, I spoke to a good garage today about the MOT and they suggested they could test it first thing in the morning to avoid any CEL from warm starts, so I might at least keep my car on the road for now! Thanks both!

 

[dukedkt442]

ANY sludge or residue on the screens or anywhere in the engine is not good. Again, don't chase red herrings until you suss out the oil pressure issue, which can't be done until you obtain a reading. You'll need to get a gauge to the oil pressure sender on the OFHG, IIRC.

Miles don't matter, metal does. You need to send your oil out to see what metal is in it. Nothing at this point should be gueswork, but instead 100% data driven. The back of my mind wonders if a serpentine belt was ever tossed on this car.

Here's what my screens look like, closing in at 200k miles. Look a little bit different, eh?

 

[Watchme]

So for the price of valve cover, I also spent some time researching. In the end I bought OEM from FCP - and certainly paid quite a bit: around 450 pounds if I converted from freedom dollars correctly. The cover is a huge pain to replace, so I wanted to only do it once. Other brands are much cheaper, but you may pay the price if it doesn't fit right / leaks.
Also not sure if the unfiltered oil can explain the sludge on your non-return valves. I'll post mine later, not as clean as duke, but still clean.
I got curious about oil pressure test. For N52, someone hosted the procedure below.

https://f01.justanswer.com/SCCARDOC/99f096b9-f4b8-4c12-8c4d-6b94a257af98_2008_BMW_528I_OIL_PRESSURE.pdf

I already linked the kit for test above. You'd want something similar. The kit already has the needed M12 x 1.5 male adapter. But I wouldn't expect high quality threads on it, so you may consider ordering the adapter separately from non-china supplier. Some insights for the adapter (BMW 11 4 050) Oil Pressure Adapter
For the oil pressure values, I can give you those if you provide 7 of the vin. For my N51, the specs are below.

11 41 Oil Pump with Strainer and Drive N51 B30
Oil pressure at idle speed with engine at operating temperature min bar 1.5
Control pressure with engine at operating temperature bar 4.0...6.0

 

[e92countryboy]

ANY sludge or residue on the screens or anywhere in the engine is not good. Again, don't chase red herrings until you suss out the oil pressure issue, which can't be done until you obtain a reading. You'll need to get a gauge to the oil pressure sender on the OFHG, IIRC.

Miles don't matter, metal does. You need to send your oil out to see what metal is in it. Nothing at this point should be gueswork, but instead 100% data driven. The back of my mind wonders if a serpentine belt was ever tossed on this car.

Here's what my screens look like, closing in at 200k miles. Look a little bit different, eh?
View attachment 1065675

Wow, that's stunningly clean. They really came out without even oil on them?

I appreciate the help from both you and Watchme, but the car was involved in a low speed RTC this evening that the insurance is expecting will write it off as being uneconomical to repair, so I'm putting my investigative measures on hold for now until they've done their inspection. May not need to worry about that MOT after all. I really appreciate your weighing in with your experience, this forum has taught me a lot but I'm afraid it may not be relevant for this car any more. Absolutely gutted.

If the car isn't taken away by the insurance, I will put both of your suggestions into action. You can guarantee I'll be back with another E9X 330i when that payout comes through though, maybe this time with lower mileage and better service history

 

[dukedkt442]

Sucks to hear (and I’m not familiar with those abbreviations you have over there, but I surmise they’re not pleasant). Good luck.

Yes, the above pic is how the screens looked as removed. The VANOS solenoids look the same.

On the next one, peer into the cam cover and look for sludge. It should look like this (taken at 170k miles).

Via the interwebs

 

[e92countryboy]

Sucks to hear (and I’m not familiar with those abbreviations you have over there, but I surmise they’re not pleasant). Good luck.

Yes, the above pic is how the screens looked as removed. The VANOS solenoids look the same.

On the next one, peer into the cam cover and look for sludge. It should look like this (taken at 170k miles).

Via the interwebs

Sucks to hear (and I’m not familiar with those abbreviations you have over there, but I surmise they’re not pleasant). Good luck.

Yes, the above pic is how the screens looked as removed. The VANOS solenoids look the same.

On the next one, peer into the cam cover and look for sludge. It should look like this (taken at 170k miles).

Via the interwebs

My bad, RTC is road traffic collision, what the police officially call a crash haha. Low speed but at a bad angle so damaged quite a few pieces of bodywork. No one hurt.

The MOT is our annual roadworthiness test for cars over 3 years old. Among many other things, they test that the CEL turns on when started and then turns off again. If it stays on, instant fail and your car doesn't go on on the road till it's sorted. Hence my worry, this being my only car and needing it for work!

I haven't put a proper scope down the oil filler to inspect the VANOS units yet. I noticed shortly after buying it that there were small deposits between the coils on the Valvetronic springs visible from the cap, but thought nothing of it. After comparing to how it looks in your pictures, I'd take that as evidence of sludge too. Unfortunately I don't have pictures on me right now. Perhaps my sludge was worse than I thought.

Once the insurance has cleared everything and I can post images, I'll get some advice about what to do about the car; damage, service history and sludge considered. Thanks again for your help up to this point.