Metallic Rattle 2-3k rpm

[Darbshaw]

Hello all!

I’ve recently had an issue with my M where I’m getting some sort of metallic rattle sound between 2-3k rpm. I would say like the equivalent to rattling the ICV when you’re cleaning it. This sound is only apparent between these rev ranges and at like quarter throttle. WOT and light throttle cuts the sound completely.

I originally thought this was my hanging front skid plate (plastic one) that I’ve been too lazy to rig back up, but at this point I’ve completely decided against that due to the sound.

I’ve been racking my brain trying to figure out what my potential issues could be and can’t really see any that would make sense from the posts I’ve found online already.
Currently I’ve been chasing some intermittent misfire issues with the car and some rougher idle with a little bit of rpm hunting. The misfires have been without cylinder cutout. Along with that there has been an occasional code for coolant temp implausible. I recently threw some codes but my laptop is dead and I’m at work. If I had to guess it will be the same recurring codes

What’s been done (Current 164k mi):
Full Vanos fix (anti rattle, timing chain guide, etc) roughly 4K miles ago
New plugs and coils approx 5k miles ago
Fuel pump less than 1000mi
Rod bearings @approx 140k by PO
New MAF 2k miles ago

Mods:
Megan Racing headers
Agency power sec 3
Build Journal B-Spec Tune

Yet to do:
New injectors/clean (this ones a little harder because I really don’t want to be down a car for a week)
Compression test

Edit: added more fixes done

Sent from my iPhone using Tapatalk

[SteelGreyM]

Wow. Might as well be my car. I had been scratching my head at the exact same issue as you for months. Ended up being a blown head gasket between every cylinder.

I also had the coolant temp code, buildjournal tune, 2-3k rattle at quarter throttle. I’d get a compression test done ASAP!

[Darbshaw]

Wow. Might as well be my car. I had been scratching my head at the exact same issue as you for months. Ended up being a blown head gasket between every cylinder.

I also had the coolant temp code, buildjournal tune, 2-3k rattle at quarter throttle. I’d get a compression test done ASAP!

Oh god that’s not what I’m wanting to hear (
I haven’t had any issues or low/lowering coolant levels so I’ve written that off.

Did you diy yours or goto an Indy? What were the costs of the job for you? Luckily I work across the street from like the only euro Indy in West Virginia. I’ll see if they can get my car in for a test today. Lack of a compression tester and I figure this will be a quicker answer as long as it’s not too expensive.


Sent from my iPhone using Tapatalk

[SteelGreyM]

I let the problem go on for WAY longer than I should have simply because I couldn’t diagnose it. So I had many more complications than you might. If I had caught it earlier I couldn’t gotten away with a standard head gasket job.

If you don’t know what you’re doing I’d leave it with a professional. Compression test is simple and cheap enough. I’d start there.

Also, I’m not saying that the head gasket is your culprit. But I am saying your symptoms sound exactly like mine and a few other cars I have read about. That rattling is actually pre detonation.

[Darbshaw]

What were some of the complications that you ran into? At this point it’s been going for a week or so and it may be a little longer till I can go pickup my old car from my other work lot.

Doing it diy wouldn’t be too much of an issue. I have one of our shop mechanics that’s a good buddy that I can bribe for the extra hand. Just a matter of pricing I guess.


Sent from my iPhone using Tapatalk

[SteelGreyM]

Mine went on for months. I didn't even hear it half the time because once you really start driving (4krpm+) the detonation goes away. My guess is that you be ok. Might have to skim the head a touch is all.

Because mine went on for so long it eventually decided to break my piston. Im currently getting a rebuild because of all this.

IM NOT SAYING YOU NEED A REBUILD. All im saying is that I would at least get a compression test to eliminate this possibility.

[Darbshaw]

Mine went on for months. I didn't even hear it half the time because once you really start driving (4krpm+) the detonation goes away. My guess is that you be ok. Might have to skim the head a touch is all.

Because mine went on for so long it eventually decided to break my piston. Im currently getting a rebuild because of all this.

IM NOT SAYING YOU NEED A REBUILD. All im saying is that I would at least get a compression test to eliminate this possibility.

Okay hopefully the rebuild is far out the window for now! Walked over to the Euro shop and they said 75 bucks for a compression test so I figure I’ll just buy a tool and run it when I’m at home tonight or something.

I was thinking about it and this issue became prevalent after my most recent oil change where I ran a Liqui moly engine flush and I’m starting to think it pushed it over the edge


Sent from my iPhone using Tapatalk

[OEMaddict]

Keep in mind this is an extreme example, but does the rattling sound like this? LOTS of documented info on m3cutters. And what was the actual code that your car threw regarding coolant temp? I have the same symptoms as you, just got the coolant temp (P0128) code last week on startup. Compression test done 5+ years ago on startup, all cylinders were low around 140.

[SteelGreyM]

Keep in mind this is an extreme example, but does the rattling sound like this? LOTS of documented info on m3cutters. And what was the actual code that your car threw regarding coolant temp? I have the same symptoms as you, just got the coolant temp (P0128) code last week on startup. Compression test done 5+ years ago on startup, all cylinders were low around 140.

Mine didn’t sound like this. This sounds raspy. OP provided a great example of the noise. It sounds like a clean ICV when on the throttle.

[heinzboehmer]

Mine didn’t sound like this. This sounds raspy. OP provided a great example of the noise. It sounds like a clean ICV when on the throttle.

Was the sound closer to this?

https://www.youtube.com/watch?v=U0xWd72f4g8

[Darbshaw]

Here are the compression test results, my understanding from this is that my issues are running deeper than just the head gasket.


Sent from my iPhone using Tapatalk

[Darbshaw]

Was the sound closer to this?

https://www.youtube.com/watch?v=U0xWd72f4g8

That was a lot more like the sound mine is having. Definitely not as pronounced and as raspy as the other one.

[su45]

Build Journal B-Spec Tune

buildjournal tune

I feel like this tune has been the common denominator in the past 3-4 blown head gaskets I've seen here. Does it code off the knock sensors or something?

[Darbshaw]

I feel like this tune has been the common denominator in the past 3-4 blown head gaskets I've seen here. Does it code off the knock sensors or something?

My understanding is that they have some sort of tune in it that reduces the knock sensor sensitivity or something like that. Where I have mine specified for 93 octane. I've obviously ran nothing but 93 but this could most definitely be the cause.

[LSBNick]

So I have a similar sound yet it’s only when the car is cold. Mine happens right when I hit 3k, anything below or above the sound disappears. However mine sounds like more of a clutch/flywheel sound than anything. No clutch slippage notices and the car drives perfectly fine. Once warmed up (roughly 10 min of driving) the sound is gone entirely.