[Marq_z]

Hi All,

As most of us know, our cars are prone to making all sorts of noises that can trigger our ocd. No one wants to think that something's potentially wrong with their car! After looking all over the internet searching for someone with my same issue, I've decided to just ask bc I cant find an example that's similar to the noise I'm hearing coming from my engine bay! I would greatly appreciate any insight and or validation that my N55 isn't a goner...

Here's the break down:

I bought my 2012 335i sportline about 3 months ago with 73,000 miles on it. After the initial excitement started to ware off a bit I started to notice a KNOCKING SOUND coming from the engine bay that can be heard from inside. Initially I didnt pay much attention to it since the car has been running smoothly without issues, aside from a drivetrain malfunction I experienced, which was resolved with new plugs as the original ones were going. I've since been looking into the noise, but the more I research the more I freak out about potential problems like looking up the symptoms for a cold on WebMd and realizing you have 2 weeks to live. The noise is not there at all on cold start. It's only present once I've driven for awhile and the engine is at operating temperature and at idle. Once I start moving it goes away. It's NOT the injectors as they make a different clicking noise. Has anyone had this same noise coming from their engine bay and is it normal or is there something else going on?

UPDATE:
Indy shop noticed torque converter bolts were loose. They tightened them and noise went away.

[T_H_O_M_A_S]

have you tried without running the engine cover ? maybe it rattles on its mounts ?
always difficult to point out the culprit in such a thread

[thejeremyman9]

You didnt rev the car up at all so we have no way of knowing how this noise varies with RPM, if at all. That is a key test.

You can try to get a mechanic's stethescope and touch it on various parts of the engine to see if you can pinpoint where it is coming from.

[Marq_z]

Originally Posted by thejeremyman9

You didnt rev the car up at all so we have no way of knowing how this noise varies with RPM, if at all. That is a key test.

You can try to get a mechanic's stethescope and touch it on various parts of the engine to see if you can pinpoint where it is coming from.

I'll try to do that this weekend and will try to locate the source. I just hope it's nothing major..

[Marq_z]

Originally Posted by T_H_O_M_A_S

have you tried without running the engine cover ? maybe it rattles on its mounts ?
always difficult to point out the culprit in such a thread

I hadn't really considered the engine mounts but I'll look into it this weekend. The noise is still there with the cover off.

[Marq_z]

Originally Posted by thejeremyman9

You didnt rev the car up at all so we have no way of knowing how this noise varies with RPM, if at all. That is a key test.

You can try to get a mechanic's stethescope and touch it on various parts of the engine to see if you can pinpoint where it is coming from.

Here is another video I took today. Still cant seem to figure this out. I's frustrating that it only happens when the car is hot.

https://youtu.be/w3934PA4gt4

[Marq_z]

Originally Posted by Marq_z

Here is another video I took today. Still cant seem to figure this out. I's frustrating that it only happens when the car is hot.

https://youtu.be/w3934PA4gt4

[ctt300]

Sounds like a rod bearing. I would not drive it until all of them are replaced.

[obeeone]

Yeah. It does sound like a bottom end issue. I have not worked on these cars much, but you could disconnect coil packs one at a time while the car is running and see if the noise gets quiet or quits on any particular cylinder. That's how we used to identify missing and or rod knock issues when I was working on cars years ago.

[Marq_z]

Originally Posted by obeeone

Yeah. It does sound like a bottom end issue. I have not worked on these cars much, but you could disconnect coil packs one at a time while the car is running and see if the noise gets quiet or quits on any particular cylinder. That's how we used to identify missing and or rod knock issues when I was working on cars years ago.

I actually did that this past weekend. I unplugged coils one at a time and the thump/knock was still there after the initial hesitation from the engine which gives me some hope that its not a problem in a cylinder. I also listened for it under the car around the oil pan but nothing. The places where the sound was most pronounced were by the turbo/exhaust manifold and the throttle body/intake manifold. I also found this post about a pcv valve failure with the same sound that I have.
https://bmw.***********.com/threads/...ay-sound.3008/

Anyway, I'm taking it in to an indy shop this Saturday. We'll see if they can find the source. Fingers crossed.

[rmaringa]

I have a similar problem, did you find a fix.. Mine has been going on for 5 years no one can fix it, here is a video

[FancyTie]

Originally Posted by rmaringa

I have a similar problem, did you find a fix.. Mine has been going on for 5 years no one can fix it, here is a video

Injectors lol... I had a Cobalt SS Turbo before and all of them have this "problem". I had 3 of them and all 3 did this. I've asked 5000 cobalt owners and they said the same.

I know Chevy and BMW ain't related at all but that's the sound of injectors 100%. If no one have found this for real never go back there ahah. I know that's a common problem on N54 engine.

[rmaringa]

Thank you, I will direct my next mechanic to look into the injectors and give feedback
Here is a clearer video for better diagnosis

[rhmarquez]

Originally Posted by rmaringa

Thank you, I will direct my next mechanic to look into the injectors and give feedback
Here is a clearer video for better diagnosis

The sound in this video seems like either the Fuel Injectors or the Accessory Belt Tensioner. Look for the belt tensioner in front of the engine and see if it's vibrating. Mine had play and was making a very similar noise. From what I've read they seem to go bad around 100k. It's a pretty easy DIY to replace it. There's a video from KiesMotorsport in YouTube that tells you how to diagnose/replace it.

[rmaringa]

Originally Posted by rhmarquez

The sound in this video seems like either the Fuel Injectors or the Accessory Belt Tensioner. Look for the belt tensioner in front of the engine and see if it's vibrating. Mine had play and was making a very similar noise. From what I've read they seem to go bad around 100k. It's a pretty easy DIY to replace it. There's a video from KiesMotorsport in YouTube that tells you how to diagnose/replace it.

Thank you, my car just passed the 100k mark. I will check the video

[Marq_z]

Originally Posted by rmaringa

I have a similar problem, did you find a fix.. Mine has been going on for 5 years no one can fix it, here is a video

This is not the same sound. What you hear in your video are the injectors ticking and possibly a bad pulley which is normal and not cause for concern. A lot of bmw owners complain about the loud ticking from injectors but this is normal and a product of direct injection. The clock ticking might be from a bad pulley, belt tensioner or old belt. I'd just buy a kit and replace the parts, its fairly easy to do. My noise came from the torque converter. Sounded like a helicopter but there wasn't any real issue, just noisy.

[rmaringa]

Originally Posted by Marq_z

This is not the same sound. What you hear in your video are the injectors ticking and possibly a bad pulley which is normal and not cause for concern. A lot of bmw owners complain about the loud ticking from injectors but this is normal and a product of direct injection. The clock ticking might be from a bad pulley, belt tensioner or old belt. I'd just buy a kit and replace the parts, its fairly easy to do. My noise came from the torque converter. Sounded like a helicopter but there wasn't any real issue, just noisy.

Wow, thanks I'll look into it

[thejeremyman9]

Originally Posted by rmaringa

Wow, thanks I'll look into it

There's one key piece of information missing here - is the noise RPM dependent or not? Any difference between P/N/D?

[rmaringa]

Originally Posted by thejeremyman9

There's one key piece of information missing here - is the noise RPM dependent or not? Any difference between P/N/D?

No difference, it is the same on P/N/D and it is not RPM dependent

[rmaringa]

Originally Posted by Marq_z

This is not the same sound. What you hear in your video are the injectors ticking and possibly a bad pulley which is normal and not cause for concern. A lot of bmw owners complain about the loud ticking from injectors but this is normal and a product of direct injection. The clock ticking might be from a bad pulley, belt tensioner or old belt. I'd just buy a kit and replace the parts, its fairly easy to do. My noise came from the torque converter. Sounded like a helicopter but there wasn't any real issue, just noisy.

Changed all the pullies and belt, by the way the crank shaft was vibrating.. but the tapping continues

[David Kunitz]

Originally Posted by Marq_z

https://youtu.be/w3934PA4gt4

Sorry to bring back an old thread.

I am having the exact same issue as you are on my 2012 335i F30.
Did you ever find a fix?