[Joshgoble4]

Hi I am new to this forum so please let me know if there’s problems viewing the attached video. Back in July I bought a e90 335i 2007 and after about 3 weeks of ownership it started knocking at the beginning of my commute to work. I let the car warm up about halfway to the 220 degrees when usually I would’ve waited a bit longer. Then I leave my house and before I even got out of my neighborhood this sound started (was probably going 30-35 mph).

I have been trying various things over the past few months trying to diagnose with no success. First important piece of info is that this did not trigger any CEL when it happened - the car computer seems to have no idea that anything is wrong.

The first thing I did after limping it home was drained the oil and pulled the oil filter to look for metal. Didn’t see any but I did a blackstone oil test just to be on the safe side and result came back as a good healthy engine. Next thing I checked were belt pulleys so I ran the car with the belt off and the noise persisted.




https://youtube.com/shorts/pLkJ28bNKOs?feature=share

[Joshgoble4]

CONTINUED

Next thing I tried was checking my spark plugs which looked good and ignition coils which I swapped out with the ones in my n52. Still the noise persisted. Next I removed the valve cover and manually cranked the engine (using the crank pulley bolt) to see if any of the lifters were moving weirdly. Couldn’t see anything wrong when I tried this but still could be a lifter I think. Last thing I did was try disconnecting each fuel injector to see if the noise would go away (I don’t like inducing rough running but I was running out of ideas).

At this point I don’t know what else to try. Other than the ugly noise the engine runs normal and still has no CEL. If you made it this far thank you for reading and anyones expertise would be greatly appreciated!!

Thanks, Josh

https://youtube.com/shorts/pLkJ28bNKOs?feature=share

[Bimmer_Bro]

Yikes does your car always struggle to start like that? Your battery or starter seems very weak as well.
Sounds like rod knock to me, maybe you have spun a bearing ? (Just a guess)

[Joshgoble4]

Oh yea the video I posted was the first startup in several weeks hence why it sounded so rough. And wouldn’t evidence of a spun bearing always show as metal shaving in the oil? I didn’t investigate any further by pulling the oil pan of anything once I got good oil test results back

[Bimmer_Bro]

Originally Posted by Joshgoble4

Oh yea the video I posted was the first startup in several weeks hence why it sounded so rough. And wouldn’t evidence of a spun bearing always show as metal shaving in the oil? I didn’t investigate any further by pulling the oil pan of anything once I got good oil test results back

Very true there probably would be metal shavings. Sounds nasty for sure. When you pulled the filter, did you replace it? Iv heard stories of bad sounds coming from the oil filter area if they get clogged.

[feuer]

Yeah, rod knock. Oil analysis report showing that rod bearings failed or that are failing is just a car forum anecdote.

[Joshgoble4]

Haven’t replaced the filter yet was planning on changing oil and filter after I get this sorted but maybe I should just go ahead with it. And so I’m assuming the only way to check a for a spun bearing other than checking the oil, would be to pull the pan and check them myself. This is the job I’ve been avoiding considering it’s a lot of work just to find out that you need a new engine.

[Bimmer_Bro]

Originally Posted by Joshgoble4

Haven’t replaced the filter yet was planning on changing oil and filter after I get this sorted but maybe I should just go ahead with it. And so I’m assuming the only way to check a for a spun bearing other than checking the oil, would be to pull the pan and check them myself. This is the job I’ve been avoiding considering it’s a lot of work just to find out that you need a new engine.

Oil filter is a long shot. It honestly sounds like your engine is toast. There is no mistaking that sound

[Joshgoble4]

So at this point pulling the pan and looking to confirm rod bearing failure would probably be the only option. Anything else anyone would recommend trying? Cuz that seems like about all I can do.

Also when I listen to the sound it sounds like valve cover area but I have tested everything that I think it could be there

Either way thanks for y’all’s reply’s.

[Joshgoble4]

When I originally took oil for the sample I drained all of it and looked very closely in it but couldn’t visually see any glitter. I ended up putting this oil back in the engine (until I figure this all out, then I’ll change for fresh).
As for when I was turning over the engine by hand, it felt smooth and fluid as it should. It turned exactly how it should by hand, no hard spots or weird clicks or anything that you’d expect with a significant mechanical failure.

Once I verified that manually turning the engine felt fine, that’s what led me to look at some of the electrical components around the valve cover. Which that’s where the noise seems to be coming from anyways! Literally sounds like a woodpecker pecking away at the valve cover in perfect sync with the engine!

As for the rough start, it starts right up now since I’ve been running it more because that video was the first time in at least a couple months I had started it.

Just in case it exploded I wanted to have a video documenting it of course.

And also yes I did unplug fuel injectors and the knocking was still present for each injector being unplugged.

Overall I’m still confused but might aswell drain the oil and look at it again since it’s been a while. It’s still something until I figure out other things to try so

[n54335i02121997]

Originally Posted by Joshgoble4

When I originally took oil for the sample I drained all of it and looked very closely in it but couldn’t visually see any glitter. I ended up putting this oil back in the engine (until I figure this all out, then I’ll change for fresh).
As for when I was turning over the engine by hand, it felt smooth and fluid as it should. It turned exactly how it should by hand, no hard spots or weird clicks or anything that you’d expect with a significant mechanical failure.

Once I verified that manually turning the engine felt fine, that’s what led me to look at some of the electrical components around the valve cover. Which that’s where the noise seems to be coming from anyways! Literally sounds like a woodpecker pecking away at the valve cover in perfect sync with the engine!

As for the rough start, it starts right up now since I’ve been running it more because that video was the first time in at least a couple months I had started it.

Just in case it exploded I wanted to have a video documenting it of course.

And also yes I did unplug fuel injectors and the knocking was still present for each injector being unplugged.

Overall I’m still confused but might aswell drain the oil and look at it again since it’s been a while. It’s still something until I figure out other things to try so

Dude did you ever figure this out? My BMW has been well maintained its whole life and has never given me any trouble. Started making the same exact noise but mine is coming from the bottom of the car instead of the top. No glitter in the oil.

[apexxx6789]

Injectors do make a lot of noise... Not sure if ur issue is RPM depended but ive experienced a change in ticking and it ended up being my spark plugs not being torqued correctly. Hobby mechanic, replaced a dozen + spark plugs by feel with no issues until i came across the N54 lol.

https://www.youtube.com/shorts/vhzYnnu31PQ