Please help! Odd situation

[Spacecpe]

Hi there fellows!
I found myself once again with an odd one.
Last weekend I was out cruising with a few friends in Mexico and decided to do a pull with a friend. All went well, no problems. Got to a gas station to catch some air and once I was parked I could hear a new noise from the engine that never heard before. My heart instantly sank and I was like, rod knock for sure. I shut the car off and let it cool down for a bit, restarted, sure enough the noise is still there. I try to Rev a bit and the noise doesn't get louder (like usual rod knock) but it does get quicker with rpm moving up. I decide to get back home park it and talk to my mechanic about it. He suggested to stop driving, which I don't, it's only the weekend car. So I left it as is and started thinking about a rebuild (maybe a forged engine).
Today I decided to check on the car and was like what the hell let give it a crank. Sure enough it starts and the noise is not there at all. I let it idle for a while and revved gently to see if the noise would come back. Once it warmed up a bit (maybe 5-10min) I could start to hear the clicking noise but veery faint compared to the first time I heard it. Now I'm even more confused that ever. From what I know, once an engine develops rod knock or the bearings are worn, the cold start shouldn't be any different.
I'm attaching a couple videos to explain a bit and get more insights if possible.
1st videos is the second I heard the noise last week, the 2 other are from tonight with the cold start.
[u2b]https://youtube.com/shorts/hIJDhmg2k2M?feature=share[/u2b]
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[u2b]

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[Boosted M5]

Originally Posted by Spacecpe

Hi there fellows!
I found myself once again with an odd one.
Last weekend I was out cruising with a few friends in Mexico and decided to do a pull with a friend. All went well, no problems. Got to a gas station to catch some air and once I was parked I could hear a new noise from the engine that never heard before. My heart instantly sank and I was like, rod knock for sure. I shut the car off and let it cool down for a bit, restarted, sure enough the noise is still there. I try to Rev a bit and the noise doesn't get louder (like usual rod knock) but it does get quicker with rpm moving up. I decide to get back home park it and talk to my mechanic about it. He suggested to stop driving, which I don't, it's only the weekend car. So I left it as is and started thinking about a rebuild (maybe a forged engine).
Today I decided to check on the car and was like what the hell let give it a crank. Sure enough it starts and the noise is not there at all. I let it idle for a while and revved gently to see if the noise would come back. Once it warmed up a bit (maybe 5-10min) I could start to hear the clicking noise but veery faint compared to the first time I heard it. Now I'm even more confused that ever. From what I know, once an engine develops rod knock or the bearings are worn, the cold start shouldn't be any different.
I'm attaching a couple videos to explain a bit and get more insights if possible.
1st videos is the second I heard the noise last week, the 2 other are from tonight with the cold start.
[u2b]https://youtube.com/shorts/hIJDhmg2k2M?feature=share[/u2b]
[u2b]

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[u2b]

[/u2b]

Can't view the videos

[Spacecpe]

That's odd.. I can see them posted and I can play them.
Here are the links
https://youtube.com/shorts/hIJDhmg2k2M?feature=share

[M5_Raz]

Videos work now. It could be bad gas too, have you tried adding some octane booster? Did you get gas from a top tier certified station?

A few years ago, one of my previous cars had developed the same knock sound and was having me worried. Then I went to a different gas station and it stopped completely over the course of a couple of fill ups.

[Spacecpe]

Originally Posted by M5_Raz

Videos work now. It could be bad gas too, have you tried adding some octane booster? Did you get gas from a top tier certified station?

A few years ago, one of my previous cars had developed the same knock sound and was having me worried. Then I went to a different gas station and it stopped completely over the course of a couple of fill ups.

Hmmmmm. Yes, I always fill up at shell and I always add half a bottle of Octanium booter.. never had a knock like because of bad fuel..
I'm worried it's early signs of rod bearing failure.

[M5_Raz]

Originally Posted by Spacecpe

Hmmmmm. Yes, I always fill up at shell and I always add half a bottle of Octanium booter.. never had a knock like because of bad fuel..
I'm worried it's early signs of rod bearing failure.

I would be worried about that too. Another thing that causes it is oil. Is your oil level in between the lines? I would change it asap and see if it fixes it.

1. I'm thinking that you might've burned more than you thought during your hard pull.

2. Maybe a bit of leaky injectors sprayed too much gas and your oil is no good anymore. Did you open the oil cap to smell it?

[Spacecpe]

Oil level always at max. I'm always careful with that.
I did open the gas cap. No gas smell.
The oil was changed 1000miles ago as well.
The issue is that I never got any codes or anything at all. Not even a slight hiccup.
I've had an issue before on my 335i with leaky injectors. Cold starts we're horrible and sometimes the car would misfire.
I think the next move is to change the oil and filter and go from there.

[Spacecpe]

Ok, I drained the oil out today and actually did find some copper in the oil and a couple specs inside the filter.
I think I might very caught it in time to save the crank.
The amount of copper is very minimal, so I'm hoping there no damage to the crank yet.
My mechanic will dive into a bearing replacement in the next couple weeks and I will update you guys.
Fingers crossed I still have some luck.

[M5_Raz]

Originally Posted by Spacecpe

Ok, I drained the oil out today and actually did find some copper in the oil and a couple specs inside the filter.
I think I might very caught it in time to save the crank.
The amount of copper is very minimal, so I'm hoping there no damage to the crank yet.
My mechanic will dive into a bearing replacement in the next couple weeks and I will update you guys.
Fingers crossed I still have some luck.

Good luck! And worst case scenario, a forged engine with 900-1000hp isn't too bad

[technician117]

Sorry to hear about this.

Keep us posted and try to get pictures of the bearings when they come out. How many miles on the engine?

[Spacecpe]

Yea wouldn't mind a forged engine, except the car would be down for a while, mostlikely the rest of the summer.. that's why I'm kinda bummed.
Mileage is at 25k

[satinof10m5]

Originally Posted by Spacecpe

Ok, I drained the oil out today and actually did find some copper in the oil and a couple specs inside the filter.
I think I might very caught it in time to save the crank.
The amount of copper is very minimal, so I'm hoping there no damage to the crank yet.
My mechanic will dive into a bearing replacement in the next couple weeks and I will update you guys.
Fingers crossed I still have some luck.

Sorry to hear about this. What grade of oil and what brand did you use?

[Spacecpe]

Liquimoly 5w40 for the past 8k. Before that the car was maintained by the dealer and very well. Went in every 4-5k miles.

[M5_Raz]

Originally Posted by Spacecpe

Liquimoly 5w40 for the past 8k. Before that the car was maintained by the dealer and very well. Went in every 4-5k miles.

That's thick for our engines. My manual recommends 0w40 or 0w30 only.

[satinof10m5]

Originally Posted by M5_Raz

That's thick for our engines. My manual recommends 0w40 or 0w30 only.

I was using 5w-40 now I'm using 5w-50. Ow40/0w30 seem to be like water.

[M5_Raz]

Originally Posted by satinof10m5

I was using 5w-40 now I'm using 5w-50. Ow40/0w30 seem to be like water.

I'm only saying what the manual recommends. Why do you run a thicker oil?

It does burn a bit more with thinner oils, but I'd take that over not having the proper viscosity at startup (where a lot of wear occurs).

[Craze]

You should use oil as per manufacture recommendations

[M5Rick]

I use Castrol edge 0w30,it says in handbook to use Castrol. As an alternative Mobil 1 0W40 and it has all the right specs A3/B4, API SN/SM as in handbook in spite of BMW not being on label.

[M5Rick]

Decided to use Edge 0W40 now as oil change is soon due,it has the A3/B4, API SN spec and same price as the 0-30 so ordered it.

[crazyinp]

Per 2016 M5 manual:

Viscosity grades
When selecting an engine oil, make sure that the engine oil has the viscosity grade SAE 0W-30. Alternatively, also engine oils with vis‐ cosity grades SAE 5W-30, SAE 0W-40 or SAE 5W-40 can be used

[M5_Raz]

Originally Posted by crazyinp

Per 2016 M5 manual:

Viscosity grades
When selecting an engine oil, make sure that the engine oil has the viscosity grade SAE 0W-30. Alternatively, also engine oils with vis‐ cosity grades SAE 5W-30, SAE 0W-40 or SAE 5W-40 can be used

Interesting, my 2016 says only 0w40 or 0w30 as an alternative. Same with my online version.

[crazyinp]

Originally Posted by M5_Raz

Interesting, my 2016 says only 0w40 or 0w30 as an alternative. Same with my online version.

Can't trust BMW, what version is your manual? Trying to figure out why mine online shows that:

Online Edition for Part no. 01 40 2 972 617 - VI/16

Thanks!