Cold start rattle 2-3 seconds then gone.

[Andratch]

Is the problem fixed or is the symptom fixed?

Why did you initially change the bearings?

There is a thread on a FB group where Robert Collins (BE Bearings) replied and said there is NO BE bearing recall in affect. AND that he has no substantiated bearing failure caused by bearings recently.

Just something to think about but if the bearings were improperly installed originally maybe they fixed the repair this go around. OR its just going to take sometime for these to "fail" too.

I don't want to sound like its all doom and gloom, but just wanted to put out another idea and for you to stay vigilant at least in the short term.

*****

Side note, years ago I bought an M Roadster with a failed rod bearing. I pulled it apart and everything LOOKED great except the bearing. I gambled and rolled a new set in it. They last 1000 miles and it knocked the bearing out again (the rod was damaged from the initial failure). So while I thought I got away with it, really it just need sometime to kill the new bearing.

I suppose we'll see in the next few months!

I initially changed the bearings because I knew they were original, and was not sure of their condition (52k miles). It was part of the baselining of the car. The original bearings that came out were actually in nice shape, with predictable but relatively minor wear.



BimmerWorld did not say there was an active recall in place for BE, they just said they were in early stages of investigating a higher than average number of failures from a specific batch. That said, there's no hiding that my new bearings were TRASHED in just a few hundred miles.

Another potential factor is that the shop that changed my bearings told me that "there is no wear in process" - so after a couple hundred miles of light load driving, I had a HPDE scheduled and I used the car in the HPDE. The WPS bearings that are in it now will get babied for the first 1k miles, all below 5k rpm.

With that in mind, I suspect the problem in my case was one of these two:

1) Issue with the bearings themselves, based on BimmerWorld's comment that the specific batch of BE bearings was showing higher than normal warranty returns for spun bearings very shortly after installation
2) Issue with the installation / torquing sequence of the bolts. The shop that installed them normally uses ARP bolts, not OEM, and may not have followed the proper torquing sequence for OEM bolts. This could be exacerbated by the HPDE.

I'm not sure which.

[George Hill]

Is the problem fixed or is the symptom fixed?

Why did you initially change the bearings?

There is a thread on a FB group where Robert Collins (BE Bearings) replied and said there is NO BE bearing recall in affect. AND that he has no substantiated bearing failure caused by bearings recently.

Just something to think about but if the bearings were improperly installed originally maybe they fixed the repair this go around. OR its just going to take sometime for these to "fail" too.

I don't want to sound like its all doom and gloom, but just wanted to put out another idea and for you to stay vigilant at least in the short term.

*****

Side note, years ago I bought an M Roadster with a failed rod bearing. I pulled it apart and everything LOOKED great except the bearing. I gambled and rolled a new set in it. They last 1000 miles and it knocked the bearing out again (the rod was damaged from the initial failure). So while I thought I got away with it, really it just need sometime to kill the new bearing.

[Andratch]

Hey everyone, just wanted to follow up on this after a week of cold starts, driving and listening for the noise.

The cold start rattle is totally gone. Definitely 100% resolved by addressing the rod bearings. Glad to see some others have been able to save their engines from this too!

[bavarian3]

yes I mean the clearance... I have read other threads on acl... good for many and some with problems

thanks for calling it out! I'll keep an eye on them

[Giulianomitaly]

by tolerance, are you referring to clearance?

I'm curious as I have ACL but no problems. only a few hundred miles on them tho

yes I mean the clearance... I have read other threads on acl... good for many and some with problems

[bavarian3]

The appearance of the removed bearings is not bad but out of tolerance,I will never install an ACL again

by tolerance, are you referring to clearance?

I'm curious as I have ACL but no problems. only a few hundred miles on them tho

[Giulianomitaly]

The appearance of the removed bearings is not bad but out of tolerance,I will never install an ACL again

[bavarian3]

Yes i used plastigauge and had a tolerance of 0.051 on all… my ex bearing is acl 6b1569h-std

What do the bearings look like now?

[Giulianomitaly]

Yes i used plastigauge and had a tolerance of 0.051 on all… my ex bearing is acl 6b1569h-std

[bavarian3]

Good morning everyone...it seems that I too have solved the problem of the noise at first start-up....my bearing had been changed 8000km ago with acl ones...2 were out of tolerance, when I installed them they were ok.. .now I have mounted everything OEM BMW hopefully

Which ACL bearings did you use? Did you plastigauge on install?

[Giulianomitaly]

Good morning everyone...it seems that I too have solved the problem of the noise at first start-up....my bearing had been changed 8000km ago with acl ones...2 were out of tolerance, when I installed them they were ok.. .now I have mounted everything OEM BMW hopefully

[Andratch]

I think that picture is reassembly, I told them I was okay with ARP bolts if they torque them to stretch specs. I'm going by today to pick up the old bolts and will post pictures.

Below is a picture of the bolts that were removed. OEM.

[Andratch]

Not sure what to make of this, but in the picture you posted with the tech torqueing the rod bolts, those appear to be ARP rod bolts.

I think that picture is reassembly, I told them I was okay with ARP bolts if they torque them to stretch specs. I'm going by today to pick up the old bolts and will post pictures.

[Slideways]

Not sure what to make of this, but in the picture you posted with the tech torquing the rod bolts, those appear to be ARP rod bolts.

[Andratch]

!! RESOLVED !!



The shop confirmed that my issue has been resolved.

No noise heard on several starts between friday and today, giving about 24 hours between each start. New WPS bearings and ARP bolts have been installed, torqued properly to spec, and we're good to go.

There's certainly a possibility that other folks' noise could be caused by other things, but as a summary, here is the sound that I experienced:

https://www.youtube.com/watch?v=LnS6MEOxo7U

Here are the symptoms I observed:

1) Rattle/knock on first cold startup (after oil pressure bled off), with a 'tempo' consistant with bottom end issues (1:1, not not 2:1 that you'd hear from top end / vanos)
2) Over a few weeks, started to hear a soft knock above 2k rpm (again 1:1)
3) I pulled an oil sample that I assume will show massive amounts of material wear, but I did not obvserve a ton of metal flake in the filter.

I tried the resolutions below with no fix:

1) New Chain Tensioner
2) New Oil Filter Housing
3) New oil/filter, 10W60 BMW Brand
4) New VANOS accumulator
5) Disable cold start cycle in ECU

The root cause turned out to be either a bad batch of bearings, and/or improper torque of the rod bolts. Either way, this noise was indicative of a failure around the bearings that could have been catastrophic. If you're experiencing this sound, don't leave it to resolve itself!