E92 M3 - Metallic clunk / grind on cold start (With 3 Videos + Image of Noise)

[Doc Oc]

Originally Posted by ///M Power-Belgium

You have the single clunk noise .

What's weird is that I haven't been able to get it to do the louder longer rattle that so concerned me awhile back. I know we call it a cold start issue, but could ambient temp be a factor? Its been in the mid 90s and higher for the last three weeks and I haven't noticed the issue during that time. Before the heatwave I noticed it every cold start. Or is it just that random?

[bradleyland]

Originally Posted by Doc Oc

What's weird is that I haven't been able to get it to do the louder longer rattle that so concerned me awhile back. I know we call it a cold start issue, but could ambient temp be a factor? Its been in the mid 90s and higher for the last three weeks and I haven't noticed the issue during that time. Before the heatwave I noticed it every cold start. Or is it just that random?

I listened to your video, and the duration of the noise is too long for a single clunk, IMO. The audio resolution isn't fine enough to show the individual impulses, but a spectrograph analysis shows a duration that isn't consistent with a single impact.

[Doc Oc]

Originally Posted by bradleyland

I listened to your video, and the duration of the noise is too long for a single clunk, IMO. The audio resolution isn't fine enough to show the individual impulses, but a spectrograph analysis shows a duration that isn't consistent with a single impact.

Bingo. I know the vid is crap but the noise seems to be 2-3 quick taps. Sometimes its as many as 7 or 8 (but very fast) and they can be much louder. I don't think my noise is the alternator thing as I can also hear that and its more of a subtle single clack.

Thanks btw

[bradleyland]

IMO, the noise you're hearing is exactly the same as the one Anom3 was experiencing. You may want to explore his coding changes if you'd like to be rid of it.

[///M Power-Belgium]

Originally Posted by Doc Oc

What's weird is that I haven't been able to get it to do the louder longer rattle that so concerned me awhile back. I know we call it a cold start issue, but could ambient temp be a factor? Its been in the mid 90s and higher for the last three weeks and I haven't noticed the issue during that time. Before the heatwave I noticed it every cold start. Or is it just that random?

My situation with the clunk noise...
I never had the rattle clunk noise , only the single clunk and only when the engine is cold .
It's not about the ambient temp , it's all about how long your car was not driven , because I can hear it in summer and winter .
My car is not my DD , so normally I have every single time the clunk noise, when not using the brake procedure.
But....when I drive my car 2-3-4 days in a row , I don't have the clunk noise.
I also noticed when I drive a longer distance about 100-200 miles I don't have the clunk noise for about 7-10 days .
Is your car your DD ?

[Doc Oc]

Originally Posted by ///M Power-Belgium

My situation with the clunk noise...
I never had the rattle clunk noise , only the single clunk and only when the engine is cold .
It's not about the ambient temp , it's all about how long your car was not driven , because I can hear it in summer and winter .
My car is not my DD , so normally I have every single time the clunk noise, when not using the brake procedure.
But....when I drive my car 2-3-4 days in a row , I don't have the clunk noise.
I also noticed when I drive a longer distance about 100-200 miles I don't have the clunk noise for about 7-10 days .
Is your car your DD ?

Almost a daily driver. I have a Nissan titan too and alternate almost daily.

Bradley, I agree completely. The video I posted is about as quiet as the noise gets. Its been much worse before....not sure why the change.

[FogCityM3]

When you think about it, a few individuals on bimmerpost have unwittingly, but collectively destroyed the value of every single M3 out there. Great for new and would be buyers or people like me who will finally get hands on cheaper parts, but still makes one wonder. Bearing scare has likely costed a lot more value destruction compared to the probability adjusted cost of replacing bearings. Be careful of what you wish for and that too much "help" or "focus on a problem" may have unintended consequences.

There are "friends with benefits" and "acquaintances with downside". I think M3 owners have been victims of the latter.

Originally Posted by bradleyland

I've got a good set of Sennheiser open headphones and a set of MDR-7506's. The problem isn't on the sound reproduction side, it's on the capture side. Cell phone microphones vary widely in quality and performance. That's besides the point though.

The point is that you're beating the drum leading people to do things like replace their main bearings based on what? The sound of a cell phone recording? That's insane. Anom replaced his bearings and this mysterious sound you're so obsessed with persisted. He ended up solving it with some coding changes. You're pushing people to replace expensive components based on an internet armchair diagnosis.

At this point, anyone who listens to you is a fool.

I'm sorry, but I find your comments irresponsible, and as someone who has repaired engines for a living, I'd tell my customers to avoid your advice entirely. You've crossed over to some strange kind of fanaticism where every ticking noise you hear in a video is the boogey man, requiring a main bearing replacement AOMG ASAP.

I'm not saying these people should ignore the sounds their engines are making. I'm saying they should go visit a repair shop that can do things like send the oil off for a Blackstone report, measure oil pressure, and listen in person. They could do without someone screaming "ZOMG YOUR MAIN BEARINGS ARE GOING TO FAIL" at every tick or clack.

[redpriest]

If the value goes down enough, I'll be able to buy a couple spare M3s to scavenge parts off of and drive my car forever!

[Doc Oc]

So a week ago I added about half a quart of Lucas synthetic oil stabilizer. Haven't heard the noise since!? While the sound varies, I don't think I've ever had a cold start without at least a single clack, but none since I added the Lucas. Possibly a coincidence since I haven't let the car go more than 36 hours without driving, but in the past it's only taken 4-5 hours of sitting to make it happen. Keeping fingers crossed and will report back if the noise returns.

[anom3]

not going to say if its good or bad, but:

be careful with that stuff... it tends to quiet the motor (not just of bmws / m3s, all motors) because it in essence thickens your oil up... quite a bit.

10w60 is already quick honey like (when cold)...

Originally Posted by Doc Oc

So a week ago I added about half a quart of Lucas synthetic oil stabilizer. Haven't heard the noise since!? While the sound varies, I don't think I've ever had a cold start without at least a single clack, but none since I added the Lucas. Possibly a coincidence since I haven't let the car go more than 36 hours without driving, but in the past it's only taken 4-5 hours of sitting to make it happen. Keeping fingers crossed and will report back if the noise returns.

[Doc Oc]

Originally Posted by anom3

not going to say if its good or bad, but:

be careful with that stuff... it tends to quiet the motor (not just of bmws / m3s, all motors) because it in essence thickens your oil up... quite a bit.

10w60 is already quick honey like (when cold)...

Thanks. I agree too, but I'm running Pennzoil ultra 5w40 and was looking to thicken it up just a bit. I only put in half a quart but will probably put in the other half when/if my indicator drops. Assuming its still summer of course. Not sure if I should run it in the winter. I'm going to switch to m1 when the temp drops so thickening it at all doesn't appeal to me but it may be useful too.

Surprisingly I searched for info on Lucas and couldn't find much of anything on here. I know its popular with the domestic guys but does anyone have any experience with it in the s65? I put it in because I noticed a little more valve noise on startup with the 5w. It seems to have done the trick.

[Leonardo629]

So you went thinner only to go thicker again? Most people don't use/need Lucas oil stabilizer because they just choose the correct weight to begin with.

[Doc Oc]

Originally Posted by Leonardo629

So you went thinner only to go thicker again? Most people don't use/need Lucas oil stabilizer because they just choose the correct weight to begin with.

Very helpful

[Leonardo629]

Originally Posted by Doc Oc

Very helpful

You have an excellent oil right now in your crankcase, you really should just drive the S*&t out of your car, instead of worrying about noise that's not coming from the bottom.

[Doc Oc]

Originally Posted by Leonardo629

You have an excellent oil right now in your crankcase, you really should just drive the S*&t out of your car, instead of worrying about noise that's not coming from the bottom.

Do you think there is any drawback to the stabalizer other than the slight rise in viscosity? Keep in mind I only added half a bottle. I didn't really like the way the car sounded once up to temp and I figured I'd add a little at a time to see if it quieted it, which it did....but I'm trying to find that line where I get some extra cold start protection but don't get too thin when the temp goes up. Things sound and feel better now so I'm going to ride it out like this until my next uoa and see where my viscosities are.

[Leonardo629]

Originally Posted by Doc Oc

Do you think there is any drawback to the stabalizer other than the slight rise in viscosity? Keep in mind I only added half a bottle. I didn't really like the way the car sounded once up to temp and I figured I'd add a little at a time to see if it quieted it, which it did....but I'm trying to find that line where I get some extra cold start protection but don't get too thin when the temp goes up. Things sound and feel better now so I'm going to ride it out like this until my next uoa and see where my viscosities are.

Lucas stabilizer is 45cst at 100c, you added .5qt to a roughly 10qt capacity, that's 2~2.25cst increase overall at 100C (210F). I don't think you hurt anything, but I doubt you added anymore protection either unless you add a lot more. Lucas doesn't publish a viscosity at 40c, so it's hard to guess how viscous your oil is now at start up. But no matter what, it's still lighter than Castrol/Shell 10W60 at 160cst@40C.

You just have to trust your oil I guess, Ferrari 458 Italia revs to 9000RPM, makes 125hp/liter, and it's not blowing up all because the same oil you have in your car.

[Doc Oc]

Originally Posted by Leonardo629

Lucas stabilizer is 45cst at 100c, you added .5qt to a roughly 10qt capacity, that's 2~2.25cst increase overall 100C. I don't think you hurt anything, but I doubt you added anymore protection either unless you add a lot more. Lucas doesn't publish a viscosity at 40c, so it's hard to guess how viscous your oil is now at start up. But no matter what, it's still lighter than Castrol/Shell 10W60 at 160cst@40C.

You just have to trust your oil I guess, Ferrari 458 Italia revs to 9000RPM, makes 125hp/liter, and it's not blowing up all because the same oil you have in your car.

Gotcha, thanks!

[MrPrena]

I had a the same noise as a video, but not as loud. This incident happened after not driving the vehicle for 5+days.

I am going to try this method , and I will post it as well. thanks.

Originally Posted by javarithms

OK, I think I found a solution for this if you have a 6spd transmission. I have done this 3 times now (in the morning when the noise is very audible) and I can't hear the grinding noise any more.

What I do is, before I start the car, I go through the gears 2 times (maybe once would be enough too) and then I start the car in neutral. Can somebody else try this and see if it works for them?

[RuinerM3]

For you 6MT guys, I think I might have pinpointed my problem. If I start the car and disengage the clutch very quickly I don't get the clunk. I've messed around with releasing it a bit and if I leave the clutch fully depressed on start up (like most normal people do), I get like 3-7 clicks. A few times I noticed that when I did it slower, but before the revs jumped up I would catch the clunks and feel it in the pedal.

Could be a throw out bearing or something with the clutch sticking?

[RuinerM3]

Edit: Nevermind.

Thought it could be a clutch/TOB issue, but proved myself wrong after messing around with it in the garage for a while.

[SaNGRia]

After fixing my starting issue I was laid back and felt awesome because I don't have single issue anymore So then ///M Power-Belgium caught the clunk noise on one of my starting related video I wasn't paying attention too much since I was worrying about the starting issue.

Since I don't have anymore problems, I start focusing on this unique and beautiful m powered cold start "clunk" noise this one tricked by German

So my car is sitting on the garage about 7 days and i decided to do "no make sense" Brake and shift trick on my 6MT before i start the car. And 99% i hear the clunk after parking the car like 2 or more days on cold starts.

So i recorded the video and i tried first the brake trick and then change my gears from N to 1 then 6 then N again. Press the clutch and started. Va'Laa no clunk

As i read brake trick usually works for DCT and the shift works for the 6MT i guess. I did both anyway.

Car starts on 0:25 sec.

[///M Power-Belgium]

Originally Posted by SaNGRia

After fixing my starting issue I was laid back and felt awesome because I don't have single issue anymore So then ///M Power-Belgium caught the clunk noise on one of my starting related video I wasn't paying attention too much since I was worrying about the starting issue.

Since I don't have anymore problems, I start focusing on this unique and beautiful m powered cold start "clunk" noise this one tricked by German

So my car is sitting on the garage about 7 days and i decided to do "no make sense" Brake and shift trick on my 6MT before i start the car. And 99% i hear the clunk after parking the car like 2 or more days on cold starts.

So i recorded the video and i tried first the brake trick and then change my gears from N to 1 then 6 then N again. Press the clutch and started. Va'Laa no clunk

As i read brake trick usually works for DCT and the shift works for the 6MT i guess. I did both anyway.

Glad to see it works for you also .