[NZE90]

Originally Posted by Hakentt

What did you add to this post other than insult me?

Telling you to naff off adds a LOT to this post. I think it sums up what everybody else is thinking. Sorry to insult you snowflake.

[Efthreeoh]

Originally Posted by lookalikehuuh

You literally said that flaking magnesium makes the N52 junk. Here's the interesting part, N54 and N55 engines, which have no magnesium in the blocks still utilize the same dual filter capsules fo the VANOS systems how do you explain that? Are iron blocks just junk too?

How do you explain that in the S54 BMW also includes filters for the VANOS system? Is that all aluminum engine also having magnesium failures?

How do you explain the N52s with 400Kmiles+ if they are junk?

Also keep in mind that cars with N54 and N55 engines are actually cheaper than cars with N52 engines in the used market, its not because the engines are junk, it's because the vast majority of people don't maintain their cars, don't have the ability to fix it themselves and don't understand the more complex nature of the electronic systems in these cars. This holds true for the vast majority of german cars, with a few exceptions. Audi's are a dime a dozen for cheap everywhere, all generations of BMW (including ones without any magnesium parts whatsoever). Mercedes with everything from an inline 4 to a V12...

Your logic... well has no logic behind it.

Exactly. Many of us have N52 that have reached very high mileages of 300,000 and 400,000 miles and this guy comes in some 20 years after release of the mag-block N52 and says it is junk. I just can't laugh hard enough.

[Lochstar8]

Originally Posted by lookalikehuuh

That's just old oil varnish, probably from somewhat extended oil change intervals. Nothing to worry about, just ensure you are changing your oil on time moving forward with good quality oils.

I totally agree just varnish from extended oil change intervals. The previous owner just changed oil when the computer told him so highly extended. Under my ownership it’s never seen 5000km on the same oil. But interestingly this “material” in the filter has only started under my ownership. But still the car runs great so I guess it is what it is for now.

[Efthreeoh]

Originally Posted by Lochstar8

I totally agree just varnish from extended oil change intervals. The previous owner just changed oil when the computer told him so highly extended. Under my ownership it’s never seen 5000km on the same oil. But interestingly this “material” in the filter has only started under my ownership. But still the car runs great so I guess it is what it is for now.

OP, I'm not trying to beat a dead horse here, but in my opinion, you change your engine's oil way too early. 4,000km OCI is seriously way overkill. That may be the problem. What you are seeing may be the oil additive package chemicals not completely dissolving in the oil matrix. You can research and find that changing modern oils too early is worse than letting the oil get used until the additives have been spent. The problem with cartridge oil filters is the owner can see what the filter filters. The filter is supposed to catch stuff in the oil. What you are seeing may be completely normal for oil that is still new. Below is the oil change data for my N52 that went 426,800 miles before a flood event this past May 2025 totaled my E90. At that age the engine was consuming 1L every 2,500 miles or so and still was returning my lifetime fuel consumption average of 27 MPG (i.e. the N52 was running perfectly fine). BMW enthusiasts way over analyze their oil choices and change schedule. In my opinion, using the correct oil filter is more important than the brand of oil (as long as it meets BMW's LL-01 spec and is the correct recommended viscosity).

My 2 cents.

[sonofsun]

LOL. Seeing all the modern junk cars. E90 BMWs have their quirks but boy are they way more reliable than any other German car or any of the modern crap that don't last 100,000 miles or are not repairable.

Wife still gives me grief about holding onto the BMW and working on it every few months working on stuff that break around 150,000 miles but none of my other cars drive like the E90. There's a special bond between me and the road. My little one absolutely loves it too more than the other cars (Macan, RX350 and ES350).

[Lochstar8]

Originally Posted by Efthreeoh

OP, I'm not trying to beat a dead horse here, but in my opinion, you change your engine's oil way too early. 4,000km OCI is seriously way overkill. That may be the problem. What you are seeing may be the oil additive package chemicals not completely dissolving in the oil matrix. You can research and find that changing modern oils too early is worse than letting the oil get used until the additives have been spent. The problem with cartridge oil filters is the owner can see what the filter filters. The filter is supposed to catch stuff in the oil. What you are seeing may be completely normal for oil that is still new. Below is the oil change data for my N52 that went 426,800 miles before a flood event this past May 2025 totaled my E90. At that age the engine was consuming 1L every 2,500 miles or so and still was returning my lifetime fuel consumption average of 27 MPG (i.e. the N52 was running perfectly fine). BMW enthusiasts way over analyze their oil choices and change schedule. In my opinion, using the correct oil filter is more important than the brand of oil (as long as it meets BMW's LL-01 spec and is the correct recommended viscosity).

My 2 cents.

Attachment 3855447

That’s certainly a possibility as oil changes were longer prior to my ownership and this really only started happening during my ownership. I use a MANN HU816X oil filter which is what the car has had its entire life. As well as the LL-01 full synthetic castrol oil it’s entire life. So I guess the only real variable surrounding what I’ve done regarding oil is change frequency.

One of the main reasons I’ve been changing it more frequently is because around 4500km on an oil change seems to be the exact mileage the engine gets noticeably noisier ie: more of that glorious n52 lifter tick. Despite my driving habits not changing. Any mileage under that, or with fresh oil the car never ticks even on startup it’s genuinely one of the quietest n52s I’ve ever heard except my failing ac compressor or wheel bearings but that’s besides the point.

I could try going back to a 10k km engine oil changes and see if that makes any difference it may take a few changes to take affect. I really don’t want to go much higher than that.

I drive this car relatively hard especially in the snow covered months possibly even ice racing on the very odd occasion.

I’ll try an oil change at 10k for the next 2-3 changes and report back if I remember.(If I don’t get a new car buy then) which I probably won’t because BMW themselves barley makes a straight 6 RWD manual these days at least not one I can afford anyway.

Maybe for this first change at 5k I’ll throw a new filter in it but leave the old oil till 10k that way I can not only check up on the material but also make damn sure it doesn’t completely clog the filter. I get MANN HU816X’s at a pretty hefty discount so I don’t mind swapping filters often. Plus that will give me an idea if it gets better or worse during the first or second half of the oils life span.

Thanks for the input.

[StradaRedlands]

Lochstar8 You didn't mention if you have a short commute or not. If you're not letting it get up to operating temp for extended period (20min?), it could be keeping moisture in the engine creating sludge and making some weird mixture that your filter is correctly pulling out. Anyway, maybe not the problem at all, just throwing it out there. But wanted to emphasize the filter is doing its job as intended!

[Lochstar8]

Originally Posted by StradaRedlands

Lochstar8 You didn't mention if you have a short commute or not. If you're not letting it get up to operating temp for extended period (20min?), it could be keeping moisture in the engine creating sludge and making some weird mixture that your filter is correctly pulling out. Anyway, maybe not the problem at all, just throwing it out there. But wanted to emphasize the filter is doing its job as intended!

Your absolutely correct I did forget to mention that. My drive is about 28 minutes one way. But roughly once a week ill take the car for a longer drive or I’ll go into town after work etc which usually gets the oil temps pretty hot 105°C-110°C. On the average though my oil temps are almost always between 97°C and 102°C. Depending on outside temperature it struggles a little more to reach full operating temp like in -40°c. But little drifting solves that pretty quick. So in my case I don’t think that’s my problem.

But a very valid concern nonetheless.

[StradaRedlands]

Originally Posted by Lochstar8

Your absolutely correct I did forget to mention that. My drive is about 28 minutes one way. But roughly once a week ill take the car for a longer drive or I’ll go into town after work etc which usually gets the oil temps pretty hot 105°C-110°C. On the average though my oil temps are almost always between 97°C and 102°C. Depending on outside temperature it struggles a little more to reach full operating temp like in -40°c. But little drifting solves that pretty quick. So in my case I don’t think that’s my problem.

But a very valid concern nonetheless.

Agreed, that doesn't seem to be a contributor.

[Efthreeoh]

Originally Posted by Lochstar8

That’s certainly a possibility as oil changes were longer prior to my ownership and this really only started happening during my ownership. I use a MANN HU816X oil filter which is what the car has had its entire life. As well as the LL-01 full synthetic castrol oil it’s entire life. So I guess the only real variable surrounding what I’ve done regarding oil is change frequency.

One of the main reasons I’ve been changing it more frequently is because around 4500km on an oil change seems to be the exact mileage the engine gets noticeably noisier ie: more of that glorious n52 lifter tick. Despite my driving habits not changing. Any mileage under that, or with fresh oil the car never ticks even on startup it’s genuinely one of the quietest n52s I’ve ever heard except my failing ac compressor or wheel bearings but that’s besides the point.

I could try going back to a 10k km engine oil changes and see if that makes any difference it may take a few changes to take affect. I really don’t want to go much higher than that.

I drive this car relatively hard especially in the snow covered months possibly even ice racing on the very odd occasion.

I’ll try an oil change at 10k for the next 2-3 changes and report back if I remember.(If I don’t get a new car buy then) which I probably won’t because BMW themselves barley makes a straight 6 RWD manual these days at least not one I can afford anyway.

Maybe for this first change at 5k I’ll throw a new filter in it but leave the old oil till 10k that way I can not only check up on the material but also make damn sure it doesn’t completely clog the filter. I get MANN HU816X’s at a pretty hefty discount so I don’t mind swapping filters often. Plus that will give me an idea if it gets better or worse during the first or second half of the oils life span.

Thanks for the input.

Good on the MANN filter, that is all my N52 in the E90 ever had in it as well. Also, I used only BMW's oil LL-01 5W-30.

I know it is difficult for people to break the habit of early oil changes, but I've proven what seems to be ridiculously long drain intervals are quite tolerable with the N52. Believe me, I was skeptical at first, and had serious pucker factor when the first change went 17,000 miles and worst, the engine did not consume any oil until it needed a quart a few weeks before the OCI notification came up (I checked it twice - @ change #3 and #14 posted above). I did not trust the oil quality sensor (OZS), but the E90 when new was under BMW's pre-paid (cough-cough - free) maintenance plan.

I drove my E90 very, very hard day in and day out on the excellent back-country roads we have here in my local in the Virginia Blueridge Mountains. Just a mile from the house is an 11-turn corkscrew that drives up over a ridge, 800 feet elevation change in just 1 mile of roadway. I took that road every day for 15 years on a cold engine. And then hammered down it on the way home. A true test of the N52 lubrication system to not scavenge on high-G turns. My car also saw a lot of heavy stop-and-go traffic too on my commute. The one good attribute of my commute was the heat cycling was limited; the engine would see a good 1 hour and 45 minutes between cool down periods. There is no doubt the long heat cycle periods helped in achieving the high mileage the engine reached. But once the engine is hot, it is hot.

10 klicks on the OCI may help improve what you (won't) see in the filter.

[The Nightman]

Originally Posted by Hakentt

that is protective coating chipping away from magnesium block, all N52 have that issue, that is why N52 is junk

Fascinating. This lead me down the rabbit hole of magnesium alloys and their coatings. I wonder what conditions lead to this issue? Excess moisture in the oil? Oil becomes too acidic? Or does the coating just fail overtime? I doubt many people would even realize it was happening unless they inspect their filter media closely (even I don't). I don't think OP is looking at oil varnish as that is typically much darker in color.

I looked at a few used blocks on eBay and didn't see any with peeling coatings on the bedplate. However, I did see numerous reports of the magnesium bedplate developing cracks and the leading theory is due to inconsistent thermal expansion rates. Might be more of an issue on track cars driven hard.

Very interested to learn more. The N52 does feel like BMW's beta test of some technologies, not all of which worked out.

[The Nightman]

Originally Posted by Lochstar8

That’s certainly a possibility as oil changes were longer prior to my ownership and this really only started happening during my ownership. I use a MANN HU816X oil filter which is what the car has had its entire life. As well as the LL-01 full synthetic castrol oil it’s entire life. So I guess the only real variable surrounding what I’ve done regarding oil is change frequency.

One of the main reasons I’ve been changing it more frequently is because around 4500km on an oil change seems to be the exact mileage the engine gets noticeably noisier ie: more of that glorious n52 lifter tick. Despite my driving habits not changing. Any mileage under that, or with fresh oil the car never ticks even on startup it’s genuinely one of the quietest n52s I’ve ever heard except my failing ac compressor or wheel bearings but that’s besides the point.

I could try going back to a 10k km engine oil changes and see if that makes any difference it may take a few changes to take affect. I really don’t want to go much higher than that.

I drive this car relatively hard especially in the snow covered months possibly even ice racing on the very odd occasion.

I’ll try an oil change at 10k for the next 2-3 changes and report back if I remember.(If I don’t get a new car buy then) which I probably won’t because BMW themselves barley makes a straight 6 RWD manual these days at least not one I can afford anyway.

Maybe for this first change at 5k I’ll throw a new filter in it but leave the old oil till 10k that way I can not only check up on the material but also make damn sure it doesn’t completely clog the filter. I get MANN HU816X’s at a pretty hefty discount so I don’t mind swapping filters often. Plus that will give me an idea if it gets better or worse during the first or second half of the oils life span.

Thanks for the input.

Mileage alone is insufficient for determining oil change intervals. It greatly depends on your operating conditions. If you do city driving or short trips with more start ups and heat cycles then I would change the oil on a time based interval.

Oil is cheap and easy to DIY; you don't really gain anything by extended intervals, especially with the amount of debris you're seeing in the filter.

[Lochstar8]

Originally Posted by The Nightman

Mileage alone is insufficient for determining oil change intervals. It greatly depends on your operating conditions. If you do city driving or short trips with more start ups and heat cycles then I would change the oil on a time based interval.

Oil is cheap and easy to DIY; you don't really gain anything by extended intervals, especially with the amount of debris you're seeing in the filter.

I basically drive exclusively highway at 110-90kmh. I’d just be curious to see if extending the interval some makes any sort of difference, I suspect it won’t but who knows.
I’ve been changing it so frequently because as you mentioned oil is cheap engines aren’t. I’m a mechanic by trade and it kills me seeing overdue oil changes but not being able to do anything about it because my boss doesn’t want to spend the money unless it’s completely broken. So I change my oil very frequently or till I notice the engine gets noisy (4500km). I DIY everything on this car including powder coating the rear subframe which I did last winter.

[The Nightman]

Originally Posted by Lochstar8

I basically drive exclusively highway at 110-90kmh. I’d just be curious to see if extending the interval some makes any sort of difference, I suspect it won’t but who knows.
I’ve been changing it so frequently because as you mentioned oil is cheap engines aren’t. I’m a mechanic by trade and it kills me seeing overdue oil changes but not being able to do anything about it because my boss doesn’t want to spend the money unless it’s completely broken. So I change my oil very frequently or till I notice the engine gets noisy (4500km). I DIY everything on this car including powder coating the rear subframe which I did last winter.

In that case then any decent LL01 oil and a Mann filter should easily last at least 10k km. I'm not sure if that is wise though, considering your filter is catching so much debris.

[Lochstar8]

Originally Posted by The Nightman

In that case then any decent LL01 oil and a Mann filter should easily last at least 10k km. I'm not sure if that is wise though, considering your filter is catching so much debris.

I agree it may be unwise with the volume of material I’m dealing with but I’m going to change just the filter at 5000km that way hopefully I avoid any oil pressure issues and can re-inspect and report back on if the volume of material has changed. At least on the first 10k km oil change. It will be a test.

[StradaRedlands]

Originally Posted by Lochstar8

I agree it may be unwise with the volume of material I’m dealing with but I’m going to change just the filter at 5000km that way hopefully I avoid any oil pressure issues and can re-inspect and report back on if the volume of material has changed. At least on the first 10k km oil change. It will be a test.

That's exactly what I do half way through my 10k mile OCI. It's probably unnecessary, but an easy job as long as I don't dribble oil everywhere when the old filter comes out!

[Hakentt]

Originally Posted by The Nightman

Fascinating. This lead me down the rabbit hole of magnesium alloys and their coatings. I wonder what conditions lead to this issue? Excess moisture in the oil? Oil becomes too acidic? Or does the coating just fail overtime? I doubt many people would even realize it was happening unless they inspect their filter media closely (even I don't). I don't think OP is looking at oil varnish as that is typically much darker in color.

.

It happens on all magnesium engine parts, eventually. People that argue against me here, never rebuilt few N52 engines like me. I will have to make a video about it.

[shadE9x]

I’ve seen similar to this, turned out to be a film/varnish of some kind on the inside of the engines crankcase. Engine flush loosened up the film and it turned into this gunk

[Runnin'Rich]

Finally changed the oil on my e83 n52 x3 at 210kkm and the deposits are the same as my e91 n52 at 280kkm

[StradaRedlands]

Originally Posted by Runnin'Rich

Finally changed the oil on my e83 n52 x3 at 210kkm and the deposits are the same as my e91 n52 at 280kkm

So are you thinking it's just oil filters doing their oil filter job?

[tlow98]

Originally Posted by Hakentt

It happens on all magnesium engine parts, eventually. People that argue against me here, never rebuilt few N52 engines like me. I will have to make a video about it.

Please do! Would to to hear and see more about this :-)

[Runnin'Rich]

When i rub the flakes between finger and thumb it breaks down into more of a sandy feel.

I’m sure last time it broke down into more of a paste feel.

Whatever it is, of 100 pleets of the filter there was 5 flakes in about 20 pleats. So very minor.

Oil filter had the ‘twist’ when I took it out. Don’t know what I’m doing wrong there