Engine knock/rattle

[patrikfa]

Afters months of waiting for the snow to settle it was finally time to let it breathe. On the second day of driving I noticed this noise and knowing I've read a lot of people having issues with the rod bearings it made me really worried, but I don't want to draw any premature conclusions before checking with you.

Very apparent at around 1:20 in the video

After starting it again today i found that the noise isn't as apparent when the engine is cold as when driven for half an hour, but still present.

Car is a 2009 E92 m3 with around 40k miles.
What are your thoughts?

[anerbe]

fully warmed, run it up to 3K for a few times and video

[patrikfa]

Originally Posted by anerbe

fully warmed, run it up to 3K for a few times and video

Video above is from fully warmed, but do you need me to rev more? The sound is as most audible at low rpms as in the video. Probably still there at higher but less noticeable.

[Scharbag]

Yes - warm engine and slowly rev up to 3K to 3.5K and then let it return to idle a few times.

[EricSMG]

Originally Posted by Scharbag

Yes - warm engine and slowly rev up to 3K to 3.5K and then let it return to idle a few times.

So this is the best way to "hear" rod knock?

I'm new to this motor and trying to determine what're the normal cold-start noises. My motor is dead smooth/quiet after the initial half second or so after a cold start. I get a quick metallic sound, sometimes, just after the motor fires.... lasts no more than half a second second. Then it's dead quiet there after. Sounds like timing chain or perhaps lifters.

This seems normal to me as most motors are a bit noisy at startup since oil isn't flowing to the lifters, etc. My S54 makes a good amount of racket at start up and so just trying to understand what's "normal", and what's indicative of a problem.

Sorry for thread jack but related.

[m3jala]

I don't hear rod bearings. You would have heard it when you rev'd at 50. I hear traditional noisy lifters.

[Scharbag]

Originally Posted by EricSMG

So this is the best way to "hear" rod knock?

I'm new to this motor and trying to determine what're the normal cold-start noises. My motor is dead smooth/quiet after the initial half second or so after a cold start. I get a quick metallic sound, sometimes, just after the motor fires.... lasts no more than half a second second. Then it's dead quiet there after. Sounds like timing chain or perhaps lifters.

This seems normal to me as most motors are a bit noisy at startup since oil isn't flowing to the lifters, etc. My S54 makes a good amount of racket at start up and so just trying to understand what's "normal", and what's indicative of a problem.

Sorry for thread jack but related.

These engines (and lots of german engines) make all sorts of noises on startup. It is all normal. Tensioners, VANOS, lifters etc. All these things need oil pressure to work properly.

As for rod knock, it seems like 3K RPM ish is a good RPM range to hear it.

Cheers,

[EricSMG]

Originally Posted by Scharbag

These engines (and lots of german engines) make all sorts of noises on startup. It is all normal. Tensioners, VANOS, lifters etc. All these things need oil pressure to work properly.

As for rod knock, it seems like 3K RPM ish is a good RPM range to hear it.

Cheers,

Thank you, sir - that's my gut feeling on this. Short-lived noises upon start up are normal. Anything that persists and/or happens higher up in the rev range may not be.

I've heard a few videos of the 3k rod knock - very distinct.

[patrikfa]

Okay, so if I gather this correct it doesn't sound like a rod issue, given that the noise isn't irregular and is present on idle.
If it is the lifters as m3jala suggested, is this something to worry about?

Only thing I can say for sure is that i know that the noise wasn't there before. It's at most apparent after the 0:50 mark in the video.

[anerbe]

It sounds like a ratchet, which seems to be very pronounced when you get around 3K. You can hear it at lower RPM's, but its good to get a sweeping range of RPM.

[kyrix1st]

I only hear lifters and injectors.

[lakehoustonnative]

I’m having a similar sound on my 2013 m3. Did this end up being any kind of problem?

[Assimilator1]

[edit] Only just seen the date of this video, lol.

Originally Posted by kyrix1st

I only hear lifters and injectors.

You wouldn't hear the injectors on these (port injection aka indirect and low pressure).

Originally Posted by patrikfa

Afters months of waiting for the snow to settle it was finally time to let it breathe. On the second day of driving I noticed this noise and knowing I've read a lot of people having issues with the rod bearings it made me really worried, but I don't want to draw any premature conclusions before checking with you.

Very apparent at around 1:20 in the video

After starting it again today i found that the noise isn't as apparent when the engine is cold as when driven for half an hour, but still present.

Car is a 2009 E92 m3 with around 40k miles.
What are your thoughts?

lakehoustonnative (below answer for you too if you do have the same type sound).
Sounds like noisy tappets (lifters) to me too, if that was the first time it was run in months the oil has probably drained out of the lifters and there's trapped air in them.
Once fully warmed up give it some sustained mid to highish revs and it should clear itself.

[RocketyMan]

Originally Posted by kyrix1st

I only hear lifters and injectors.

Agreed. I hear the small clickity sound of all 8 injectors.

There does seem to be a bit lazy lifter I think I hear.