Cold start rattle 2-3 seconds then gone.

[Andratch]

Update - I sent my car over to a local indy shop to investigate this today. I'll let y'all know what they find.

[Andratch]

Clutch fan? Why didn't -- the nut is too tight?
It took me 5sec to knock the nut loose and remove it using a crescent wrench and small hammer. Don't tighten too tight, just snug then you can knock it loose even with a screwdriver handle.

In a lot of the instructional videos for replacing the oil filter, they took off the fan and fan clutch (as an assembly) to get more space, but I found it to be an unnecessary step.

That said, the oil filter housing did NOT fix my issue, so the whole thing is an unnecessary step!

[Shonky]

That's at "operating temp" though, if it makes a difference.

Oil temperature definitely will alter pressure. When cold it will be higher.

[bavarian3]

.7bar at idle

That's at "operating temp" though, if it makes a difference.

[maupineda]

.7bar at idle

[bavarian3]

Anyone try doing an oil pressure test? Not sure what spec to look for at first start though

[sapote]

Got the old oil filter housing out today, did not need to take off the fan..

Clutch fan? Why didn't -- the nut is too tight?
It took me 5sec to knock the nut loose and remove it using a crescent wrench and small hammer. Don't tighten too tight, just snug then you can knock it loose even with a screwdriver handle.

[sapote]

3 seconds does seem longer than usual. That is how long my light stays on right after an oil change.

This is the worst case with an empty filter cartridge to fill, and 3 sec is long compared to normally should be less than 2sec.

[Andratch]

3 seconds does seem longer than usual. That is how long my light stays on right after an oil change.

Agreed. Mine was off almost instantly, even right after I put in the new oil filter housing.

[eacmen]

3 seconds does seem longer than usual. That is how long my light stays on right after an oil change.

[bavarian3]

How long was your oil pressure light staying on during cold starts? Seems like if that check valve was bad then it would take longer to build pressure.

A normal amount of time, the rattle only lasted around 1 to 2 seconds

What's a "normal" amount of time in your alls opinion?

Mine stays on awkwardly long during completely cold starts. 3 seconds or so. Warm starts it goes away immediately. Wondering if I have a bad valve in the filter housing. Contrary to this I don't think I have any odd rattles.

[Andratch]

Figured I'd do a new post for EDIT 3:

To try to test the chain tensioner, I started the car (hearing the noise and then go away), removed the tensioner, got the oil out of it, reinstalled, and restarted the car. If the tensioner was failing, I expect I would have heard the noise again (Because it would be re-filling it), but i did not.

I stuck my finger in the tensioner hole, and there really just isnt a lot of play in the chain guide anyway...I'm pretty sure the spring that's inside the tensioner could hold it taut on its own. So, quite confident the tensioner is not the issue here.

[Andratch]

UPDATE 2:

Well, some not ideal news. After not starting the car for almost a week, I started it up and got the sound for 1-2 seconds.

I’m not really sure what else it could be, as my tensioner is brand new, and I had my rod bearings and VANOS done recently - I feel the shop would have notified me if they saw anything wrong with the timing chain or guides while they were in there.

My big concern is - I did find a video on youtube of the EXACT same sound:

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

And the owner says that it was connecting rod bearings. I just recently had my rod bearings replaced by a local shop a few months back, and I don't recall this sound occurring before then...perhaps something is wrong with their repair? That said, my experience with rod knock is that it's a relatively chaotic noise under load, not at cold startup and then goes away while running. Maybe something VANOS related?

EDIT:

Last night I did some research on non-BMW cars with adjustable valve timing. Found a Toyota forum where cars with their VVTi system makes a similar sound for 1-2 seconds on cold start. For them, it's the VTC/VVT actuator/cam gear rattling before it gets oil pressure. I am curious if we're experiencing something similar with VANOS. Any idea of a way to isolate this and test?

EDIT 2:

Found another video from a E39 M5 with the same noise, and they fixed it with the timing chain tensioner 🙄. Mine is new, but perhaps it's faulty....I will order a replacement from FCP and try that.

https://www.youtube.com/watch?v=6vUwx3TPgBI

[WestBankM4]

UPDATE:

It does appear that replacing the oil filter housing substantially fixed this issue.

I let the car sit for 3 days, started it up, and could not hear the rattle at startup anymore. Previously, it would only take overnight or at most two nights to hear the noise loudly for 2 seconds.

In a couple weeks, the car goes into a 1 month hybernation, so that will be the REAL test.

FANTASTIC NEWS!!!!!!!!

I was messaging Heinze last year regarding this rattling so buying all the parts prior to some of them jumping up has been a blessing. Looking forward to getting my Karbonius box on ASAP now so I can address this stupid rattle while I'm in the trenches.

Looking forward to next months update and I wish you the best of luck my friend but it sounds like we've solved it potentially.

[Andratch]

UPDATE:

It does appear that replacing the oil filter housing substantially fixed this issue.

I let the car sit for 3 days, started it up, and could not hear the rattle at startup anymore. Previously, it would only take overnight or at most two nights to hear the noise loudly for 2 seconds.

In a couple weeks, the car goes into a 1 month hybernation, so that will be the REAL test.