N42/N46 Startup Rattle - Fixed!

*UPDATE*
This worked for me only for one week, now it is back. I tried replacing oil filter housing but there was no improvement. I'm testing other solutions and I will be making a follow up video.
*END of UPDATE*
I finally fixed that annoying cold startup rattle by cleaning the oil check valve that is intergraded in to the oil filter housing on my 2001 E46 316ti Compact BMW with N42 engine and 200.000 km on the odometer.
Check out my related videos:
- N42/N46 Startup Rattle - Is Replacing exhaust VANOS the solution: • N42/N46 Startup Rattle...
- Oil filter housing & Oil cooler gasket replacement: • N42/N46 Oil Filter Hou...
- Chain and tensioner replacement: • N42/N46 Chain Replacem...
- Disassembling and inspecting VANOS units: • N42 Exhaust VANOS Disa...
- Timing procedure: • N42/N46 Timing Procedure
- High oil consumption? Valve stem seals replacement: • BMW N42/N46 Valve Stem...
0:00 Intro
0:20 Replacing exhaust VANOS unit did not fix cold startup rattle
1:25 Inspecting, testing and cleaning the check valve inside the oil filter housing
4:14 Conclusions and confirming the solution
5:53 Outro
DISCLAIMER:
BimmerZen assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. Use this information at your own risk. BimmerZen recommends safe practices when working on vehicles and or with tools seen or implied in this video. Due to factors beyond the control of BimmerZen , no information contained in this video shall create any expressed or implied warranty or guarantee of any particular result. Any injury, damage, or loss that may result from improper use of these tools, equipment, or from the information contained in this video is the sole responsibility of the user and not BimmerZen.

[@danettepatrickMP]

Love these videos! You are the only person uploading fixes for the N42 engine that is very informative. These engines may not be common in the US but here in the Philippines, these 4-pot engines are common and I love that I can find content that's specific to my car. Keep it up!

[@jurkaa]

Thanks Bimmer Zen! I’ve changed the oil housing gasket as it had been leaking, cleaned the spring and after that there is no rattle, the car starts smoothly.

[@pnevmo600]

I’ve got the same rattle after oil change. Next change I used a professional motor flush from Liqui Moly and finally the rattle is gone. So I suppose I had the same problem. Thanks for sharing!

[@robertalexandrescu9975]

Bravo! I will try this when the weather gets warmer.

[@gigimarfa877]

Just saw this after I have left you a comment on the other video, what an oil-addict this engines are !!!

[@BimmerZen]

I've created a poll where you can let us know if this worked for you: kzbin.infoUgkxMhGyVBxdIbEZNzbeQPjnAexQ7EWsdn50 Thanks!

[@cnarbatumamak8375]

I have been dealing with this problem for 4 years. it's starting to get boring. "N40 engine" I did it today the problem seems to be solved but meanwhile the sound goes up and down at idle. "thank you friend" and also It was necessary to add oil to the vehicle as oil remained from the oil log :)

[@peterastley-sparke7526]

Great job, BimmerZen !

[@sudnut]

Great video! I have wondered about this issue for years. My car still rattles on cold startup sometimes. I will be inspecting this valve soon. Also need to replace valve stem seals and do a timing chain kit. Will be following your excellent videos of course. Can you confirm that the rattle is still gone after 1 month? Subscribed.

[@wolfpark7882]

Thanks for that, just fixed mine as well

[@Rea-per]

Gonna try it tomorrow

[@mrhtb8173]

Thank you thank you thank you ❤️❤️ My car was low on oil pressure and have misfire and some times stalling I had this problem for 2 years and now it’s perfect 👍

[@burak7638]

What did U do

[@mrhtb8173]

@@burak7638 just did like the video, but it obviously didn’t solve my problem permanently, my car is getting a new engine.

[@burak7638]

@@mrhtb8173 idk whats Happening ive resetted the gm module and Coded to Factory and my Car didnt rattle today hahaa

[@nekman73]

Excellent video bro.. u share solution to this problem

[@goranferlin3797]

Yep it helped me too!! Thank you!

[@Xnosevil]

Hello, thanks for all your vids ! I have the same problem and I replace the filter housing frol BMW (240€ :( ) and the rattle at cold start continue :( I think it’s a problem of vanos but you change one with no result...I’m lost :( I don’t want to chznge all my timing chain with ex and aus vanos it’s expendive 😅 I will wait for a return after one month of your engine :) Continue your videos it’s very cool :) Th2nks !!

[@MySkullzDented]

I have a similar rattle. I replaced filter housing gasket and oil cooler gasket to fix leaks, inspected, cleaned and tested the housing and check valve thoroughly. The rattle is present a shorter moment, but still present. However, the oil cooler was absolutely filled with pieces of plastic and the check valve function also obstructed, obviously due to destruction of the chain guide, some time in the car's previous ownership. Looks like i have a fun project removing oil pan and sump ahead of me.

[@BimmerZen]

💩

[@BimmerZen]

Make sure you open the oil pressure regulator valve and clean it. Also replace it if you see any damage.

[@MySkullzDented]

@@BimmerZen I will, thanks☺️

[@brucewayne8315]

Thank you for your time to test each component for this matter! It also drove me crazy, did everything else and the rattle persisted, so i will definitely check the drain in the filter housing. However, i also have a problem which i can't solve. After the car is driven for some time and you blip the throttle pedal while in idle, it sticks really bad and the exhaust sound is different than usual - and the throttle response is slow. No codes at all. It only happens when the car is at operating temperature.

[@raphaelfalsch2706]

Hey Bruce, I have a similar problem. I have a theory on it and will check it the next time I have access to a lift to look underneath. There is a vacuum hose that is leading from the gasoline filter to the intake, it's part number 11727545323. It is supposed to help with regulating fuel pressure. Another possible cause could be leaking injectors or a vacuum leak in general. Do you sometimes smell fuel inside the cabin, coming from the AC? If so, you should replace the 8 O-rings on the injectors.

[@brucewayne8315]

@@raphaelfalsch2706 Thank you for the reply! I have taken off the intake manifold three times already - checked each injector o-ring, intake manifold gasket, also changed the CCV because i had a spare. Also the area beneath the manifold is dry, so i don’t think there is a leak there. The only thing i didn’t change is the CCV return hose to the oil pan, as well as the fuel breather hose. The only code that popped up was intake manifold pressure plausibility - also changed the MAP sensor to no avail, the same thing happens. I might do a smoke test, because i don’t know where to look anymore.

[@raphaelfalsch2706]

@@brucewayne8315 Do you also hear "hissing" from the brake booster when you are idling and in natural gear? When you press the brake pedal several times. I suspect I myself might have a leaking brake booster, although... It takes the pressure from the vacuum pump, and not the manifold, which probably makes this a separate issue 😅 Gosh, this engine is really hard to diagnose sometimes. I thought about the brake booster since the RPM sometimes drop when the engine is cold and I brake because of a red light. Shortly before the stop, the engine even rattles due to the RPM drop. Since the vacuum pump is driven by the camshaft, I suspect it might be a point of failure. I put new gaskets in it and it doesn't leak, but they are known for breaking and clicking noises, etc. But the hesitation/stuttering when doing a warm start drives me nuts.

[@brucewayne8315]

@@raphaelfalsch2706 I don’t hear hissing from the booster. I did change the vacuum pump gaskets, but the OEM outer one doesn’t fit. It still leaks, but only slightly. And there is that thumping noise from the vacuum pump when you open the oil cap. Kinda love/hate with the N42.

[@abradolflincler1563]

@@raphaelfalsch2706I know this is a year late. But I had the same problem. Is your break Pedal also hard as a rock when the car sat for a few days? If yes its 100% the Vacuum Pump. I just got mine completely replaced and it fixed the issue for me.

[@suesawa1761]

i really appreciate the effort you do explanning and detailing for every each of your videos. Btw, i have cleaned this check valve and it seems to have solved the rattle but about 2 weeks the rattle has come back progressively, does your rattle still gone?. Can you make a video about throttle body angle while the valvetronic is active? Im using a bmw scanner and it shows the throttle valve works identical as a wired one, it should stay fully open while the valvetronic is active.

[@BimmerZen]

Hi! I have to admit that it only worked for me for one week. Literally the day after I published this video the rattle was back... I decided to leave the video up because It's not a complicated job to do and it could still work for other people. Now I'm looking in to VANOS unit locking, but I haven't come to any solid conclusion. so stay tunned. Regarding the throttle body operation and valvetronic; throttle is still used to control the vacuum inside the intake manifold as it is being used to purge oil vapor via CCV. Here is a video from a fellow youtuber that has more details: kzbin.info/www/bejne/bp7Jp42vq9iZqsU

[@suesawa1761]

@@BimmerZen Hi, i believe the rattle comes from the oil getting too hot and thin from a 30 minutes or longer trip, (my rattle shows up just in that case, never before) i have cleaned the oil cooler attached from the oil filter housing and fill with coolant using a high coolant charger to ensure the oil cooler fills up and purge from the purge screw next, it worked actually, but the oil cooler being higher than the expansion tank doesnt help... i did this procedure and the oil housing check valve cleaning the same day, so i dont know really which procedure was the "2 weeks effective" About throttle body... i found on youtube a lot of people saying about bmw throttle body always open, im not confused anymore, thank you!

[@karunagk1864]

Thank You.

[@RayDavies123]

Thanks man!!!

[@11RCboy11]

THANKS

[@waynedavis1214]

Best channel I have found on youtube .Just a quick question to pick your brain .I have a N46 320i.Vehicle was towed in for me to look at .Had a crap battery in it and no spark and fuel injection. Reset DME and learned values and it started straight away. Oil level on dash said OK.I decided to drain oil and it only had 0.5L ! Replaced oil and a very dirty oil filter . Diagnostics said it had a valvtronic issue . I checked eccentric shaft bearings and everything is good.I unplugged the eccentric shaft sensor and vehicle drove like a rocket with no issues. I just suspect oil rings are shot because of no oil when it came in.Next day vehicle cant rev up and compression comes and goes from 0 to over a 100 Kpa and starts and dies . Only thing I can think of is fuel washing oil off cyl walls. Im about to give up and tell them to just tow it away .Either something is blocked or I realy dont know .

[@BimmerZen]

Hi! Contact me on [e-mail]

[@gst_6377]

Love it

[@Seeeeyaaaa]

Good info, thanks BimmerZen. I just performed a full strip/clean/reseal on my N46B20 filter housing and cooler and my car runs noticeably quieter and better after doing so. I degreased the entire filter housing and check valve with degreaser and brake clean solvent and then blew it out with compressed air and did the same with the cooler. Lots of sludge came out of the cooler passages. I kept flushing it until clean solvent came out and then blew it out with compressed air, it seems to have fixed the problem for me.

[@BimmerZen]

Thank's for the info!

[@burak7638]

İs it still okay ?

[@Seeeeyaaaa]

@@burak7638 Yes, running better than ever.

[@burak7638]

@@Seeeeyaaaa did U had the cold start rattle

[@Seeeeyaaaa]

@@burak7638 yes, it also had a check engine light that was resolved by doing this fix. The engine runs nicely now. I think the oil cooler was partially blocked. Perhaps everytime the seals begin to leak the housing and the cooler should be stripped and cleaned.

[@breakthroughracing3629]

nice

[@skdenes01]

Hello, do you have some idea, about camshaft seal upgrade ? I have problem with the adaptation and also ISTA showed, intake camshat angle not reached. Anyway, have you solved the issue ? thanks

[@Trinitrotolaissance]

The cold start rattle does not happen the next morning when I keep the car at around 2000RPM for a second and then shut it off while keeping it at that RPM. I suppose one or both VANOS units are filled with oil at that RPM to change camshaft timing and it stops the VANOS from rattling due to normal wear and/or draining oil overnight when being shut off in that position. Or perhaps otherwise not locking properly all the time when shutting the car off from normal idle RPM. I've tested this at least 10 cold starts now (overnight, or 8-12 hours later same day), not a single rattle. Very healthy initial pickup to around 1800RPM as well, then regular 1100RPM cold start idle. I don't really suspect the chain tensioner to be the issue considering the full history and service I've done with new chain, guides tensioners etc.

[@calebrutherford9010]

I have same car which has had timing chain replaced before I bought it, when I changed oil filter I noticed broken bits of chain guide stuck in anti drain valve. I removed ofh and picked out all chain guide bits and it stopped my rattle

[@PTibor-mo1tf]

Hello could you help me, I have a bmw316 ti compact and the problem I have with it is that when I put it in first or reverse gear, its start shakeing the car if I don't turn the engine at about 2000 rpm, why is this?i see a lot of forums they say its normal because this engine was not the best engine what bmw made.I just ask you because i see you are the only person who doing this kind of videos.

[@NikolaHetfield11]

Great job. About changing gaskets for oil filter housing, is there need for prelube seals with oil or just put dry ones?

[@BimmerZen]

I think lube is not needed

[@Seeeeyaaaa]

No, just clean the gasket surfaces with degreaser first and then brake clean solvent for final clean, then reinstall new gaskets.

[@bartsprengelmeijer4825]

Cant hurt to pre lube with oil

[@NikolaHetfield11]

Thanks guys! ✌🏻

[@XtaticVideo]

I did this)

[@just.a_igor]

I just did clean the check valve and replaced the gasket (oil everywere) it did still make the same sound but i think oil needed to go in the oil Filter housing on the First Start tomorrow i will start the engine and i hope its gone i have the N45 engine

[@thepcmaniaccc]

Did you change the oil pickup? It can cause rattle on these engines as there is a NBR o-ring on the neck of the pickup which becomes hard as a rock after so many years, and on cold startups the pump draws air due to this and cant raise oil pressure as fast it should. Another symptom of oil pickup issue is low oil pressure light that stays on for 2-4 seconds on cold starts.

[@sudnut]

I have changed this o ring in the oil pickup for this reason and it made no difference.

[@user-gf1cg4oj9i]

Hey! Same problem. Tell me, please, do you need to drain the antifreeze before removing the filter housing? Thank you in advance.

[@BimmerZen]

No, you don't have to drain it. Oil cooler can stay connected to the cooling hoses.

[@user-gf1cg4oj9i]

@@BimmerZen That is, it can be disconnected from the oil one and nothing will flow with it?

[@luxzy7167]

hello, i have the same rattle noice on my N46 engine but it comes and goes when the engine is on. can it be the same problem you have? or something else? and when we did test exhaust side vanos test then the rattle noice come on. do you think we must change entire exhaust vanos system? sorry for bad English :DD

[@BimmerZen]

If the rattle is present when the engine is running, then this valve is most probably not your issue. I suggest checking vanos solenoids and oring seals. What test did you perform?

[@luxzy7167]

@@BimmerZen we cleaned both solenoids and changed solenoids oring seals and we think its not its not solenoids. we did the exhaust side vanos test in impa and the rattle noice came on. you think we need to change the exhaust side vanos?

[@seifdriouech9008]

Hi BimmerZen my car needs a new N42 engine. I live in Croatia and I can't find any engine for sale anywhere in the country Do you have any recommendations to where I can buy an engine in Slovenia?

[@BimmerZen]

Hi, contact me via email [e-mail]

[@MATMANPRO]

Hi, when you say `This worked for me only for one week, now it is back. I tried replacing oil filter housing but there was no improvement.` are you referring to the cleaning of the check valve only lasted a week, did you fit a new oil filter housing also but that didn`t work. Sorry but its a bit unclear as to what you mean by it only worked for a week. thanks.

[@BimmerZen]

I cleaned the check valve and used the car for one week and had no rattling on startup. But after a week the rattle came back. Then I installed used oil filter housing from another N42 engine (I cleaned it) and it didn't make any difference. But to be clear, I do not know if the other engine had this rattle or not so in theory, the replacement oil filter housing might have the same malfunction. At his point I think the rattle is a combination of slack in the chain (weak chain tensioner), leaky VANOS oil check valves (sandwitched between block and cylinder head), worn VANOS units and leaky oil filter housing check valve. When engine is hot, the oil drains from the VANOS units and chain tensioner. On the next startup it rattles until oil fills all of the components.

[@MATMANPRO]

thanks for responding, i`ve been a mech for fifty years , primarily on American cars, but with a good deal of experience on BMW. It just goes to confirm my opinion of BMW that they are over engineered and built to fail to keep those spare parts dollars rolling in@@BimmerZen

[@petrgorbounov5367]

BimmerZen's solution (cleaning+turning) is a temporary fix. Replacing the check valve gasket (worth a penny) will fix the real cause of the problem, unless the valve blockage is caused by debris coming from the oil pan. In the latter case, changing the entire housing won't help. In theory, in N46, the valve is not replaceable, but in practice it is doable. The O-ring is 11x3.5 FKM or viton (not NBR!).

[@BimmerZen]

Did yourself try this O-ring replacement?

[@petrgorbounov5367]

​@@BimmerZen No, I didn't but plan to try this on a spare OF housing. The tricks are a) to unpress the valve body and b) to find a correct O-ring. The idea is not mine, but I cannot give a link to the original post because youtube seems to delete the comments with web addresses.

[@BimmerZen]

@@petrgorbounov5367 OK, let us know if it worked for you:)

[@burak7638]

@@petrgorbounov5367 im very angry about this Problem and it triggers me every morning. Did U do it ? Guys ive read that The New chain tensioner causes this rattle The Version 3 because The Oil pressure borehole is placed towards screwhead. People got this rattle after changing To V3. After they Changed Back to V2 The rattle was gone...

[@wojtekhyla931]

Hi, can you show how to replace oil separator in N46/N24 engine without taking off intake manifold?

[@BimmerZen]

I think it's not possible to replace it without removing the intake manifold.

[@wojtekhyla931]

@@BimmerZen Thanks for your fast answer! I asked for this because I saw several entries on forums that they did it. Thanks!

[@BimmerZen]

@@wojtekhyla931 I think that it is possible on the M54 engine, but not on the N42/N46.

[@wojtekhyla931]

@@BimmerZen Thanks!

[@user-gf1cg4oj9i]

Unfortunately, I did this procedure, but the problem was not solved (

[@Trinitrotolaissance]

EDIT: the cold start rattle does not happen the next morning when I keep the car at around 2000RPM for a second and then shut it off while keeping it at that RPM. I suppose one or both VANOS units are filled with oil at that RPM to change camshaft timing and it stops the VANOS from rattling due to wear and/or draining oil overnight when being shut off in that position. Or perhaps otherwise not locking properly all the time when shutting the car off from normal idle RPM. I don't really suspect the chain tensioner to be the issue. Same random cold start rattle here for a few years now, still puzzles me but it's starting to point towards one of the VANOS units considering all the maintenance that's been done already: happens mostly when oil has been warmed up during a longer drive. But even then, it seems random and doesn't happen every cold start. Engine flush, new oil and manual check valve cleaning did not solve it. Timing chain and guides were already replaced ages ago at 265.000km (I initially thought the rattle was the chain) with newer type chain tensioner and right after that the next morning it still rattled shortly upon cold start. New timing chain did make the car run slightly smoother and when putting my ear on the valve cover, that tiny bit of chain running noise was gone. Initially when I bought the car at 186.000km it had the older type chain tensioner which caused a rattle, newer type immediately fixed that. Currently at 310.000km. I'm suspecting the whole rattle deal is one of the VANOS units being worn, most likely exhaust side. Either losing oil, or not locking itself properly when engine is turned off. When they are worn and rattle during idle, the issue is clear. But I do think these units can wear out in different ways and cause just a cold start rattle, while working properly after starting when good oil pressure is present. The rattle lasts no longer than a second, more like halve a second. I might replace both VANOS units at some point as well for *new* ones and report back. New ones being key, as I think BimmerZen might have had bad luck by installing a used unit, so I'm very interested how this is followed up. I am not aware of any other check valves in the head or block? Just the oil filter housing check valve. No other issues when driving. The N42 is a very smooth engine and pulls healthily throughout the full rev range. It's not a six cylinder, so don't expect too much torque below 1500rpm depending on gear. Avoid short trips, use good oil, change oil regularly and go for a spirited drive once in a while when oil (not coolant) is nice and warm. Take care of any of the age related stuff around the engine once it pops up and this engine will serve you for a long time, despite all the horror stories on the web. The initial 30.000km service interval by BMW no doubt set these engines up for failure later in their lives, with people driving short trips... in winter... the horror 🤯

[@burak7638]

People in German Forums Said they had chain tensioner Version 2 and Changed to Version 3 and got cold start rattle. Ive checked that and The difference between those 2 tensioners is that The Oil pressure borehole on Version 3 is closer to The screwhead which my brain tells me that we can lose Oil pressure because The Oil pressure borehole is at The end or at The Start of The chain tensioner screw. But people which got this rattle Changed Back to Version 2 (which is better than The first Chain tensioner) got rid of this cold start rattle. Unfortunately i cant find The original Version 2 Chain tensioner Just only Other Brands and im afraid to use those...

[@Trinitrotolaissance]

​@@burak7638 Thanks, I didn't know that. Interesting though that on the german forums people report good luck going from V3 to V2 again, can you link the thread? I did a bit of searching and I can confirm there is a V3 of the chain tensioner available, video here: kzbin.info/www/bejne/mYWypoxrZtSYedk Like you said, the hole in V3 is closer to the head (on the slanted part) compared to V2. The spring of V2 in that video is weaker, but that unit has probably been in the engine for a while. Another difference is that the V3 head in the video has an embossed circle on it while the V2 head is completely flat. Both have the same, thinner head compared to V1. I checked at the dealer and for N42 the part numbers are the same as mentioned in the video: Version 2: 11317567680 Version 3: 11318685091 I also just checked on my own car: currently I have V3 installed (embossed circle in the head), previously V2. So I do wonder if this might be it. From one day to another, the random rattle started. So after a while I had the chain and guides replaced, rattle was still there. I'm not 100% sure on the time frame, but I do think V2 was installed before chain and guides were replaced which was the version that was installed when the rattle started. Initially the rattle could have been the chain being worn, so I had new chain plus guides installed and V3 tensioner probably came with the kit, possible shifting the issue to the actual tensioner. I'll contact the dealer to make sure they still have #11317567680 and perhaps @BimmerZen can test this as well? I do think V2 and V3 should both have equal and improved spring pressure compared to lower V1pressure. As far as I understand, even if the tensioner has no oil in it, the initial slack (if any) of the chain is taken up by this spring pressure. Unless of course the chain itself is stretched beyond anything reasonable. Or the tensioner itself is very, very old. This is how I could pick up the slack from an older chain, going from V1 to V2 some years ago. Seeing how the oil hole on V3 is on the slanted area, I do think it is possible that the internal piston/plunger in the tensioner no longer seals that hole in the same way as V2 did. But this is speculation. I'll update if I have more info.

[@burak7638]

@@Trinitrotolaissance my Chain Guides with Chain got changed with The chain in 2017. I bought The Car in 2019. The rattle began 3 months later from The purchase. Ive Changed The tensioner even tho i already had The v3. Guess what The rattle remains. Ive Changed to 10w40 Oil because i thought some Oil gets in to The Oil Pan over night. ITS better but The rattle Sometimes is still there but got reduced. 0w40 Oil didnt help me. Ive noticed that if u Drive longer so The Oil heats Up The rattle is longer on The next day. So i guess i will try 5W50 Oil ITS thicker when its hot. Or 10W60 in Summer.

[@Trinitrotolaissance]

@@burak7638 So you changed from V3 to V2 and the rattle is still there, on N42 block? I can also confirm that it mostly or only happens after longer drives when the oil has been heated up properly. The times I did a 5 mins drive to and from the shop just to test, the next morning it would never rattle. If going from V3 to V2 in your situation, very similar to mine, didn't fix it, perhaps 5W50 or 10W60 are the only thing that stop the rattle on higher mileage cars. But I do wonder what that oil type will do with the rest of the engine as it's quite a sensitive sewing machine and appears to have strict oil requirements. What is your mileage?

[@burak7638]

@@Trinitrotolaissance no you missunderstood i Changed from v3 to v3. Not to V2. I know 1 guy He Drives Winter 5w50 Summer 10w60 on n46 . I have a N42. I will try 5w50 next time or buy v2 tensioner but its not original BMW which im afraid of

[@grantotto7301]

i know this is old vid.but im haveing trouble with startup. engine dips a bit and then idles fine.drives fine and everything. just that start up thats not nice.after standing for the day

[@BimmerZen]

Rpms dip after 1 min when it transitions from warmup phase (1000 rpm) to lower rpms (650 rpm)?

[@bigdeal87]

But if all was ok how should that fix it ?

[@BimmerZen]

Apparently, there was some backed oil residue on the sealing surfaces of the valve...

[@bigdeal87]

@@BimmerZen Ok thanks will check mine on a N43 Greetings from Swiss !

[@marcussok6469]

I have one I'm fixing, this is the major problem on n46 ; poor design from bmw

[@ismailameeroedien155]

What happens if you don't fix the rattle?

[@BimmerZen]

I suspect it is putting some additional stress on the old brittle plastic chain rail guide that can eventually break causing the chain to jump. I also suspect that it puts additional stress on the valvetronic intermediate lever springs and that could cause a break. In all honesty, I would try cleaning the oil filter housing check valve, and if that doesn't work, I would just leave it be... This rattle is really hard to get rid of, so it's easier just to fix the things if they break:)