Cold start rattle 2-3 seconds then gone.

[BL92]

I just saw this title, and thought i would share

[ac427]

I just saw this title, and thought i would share

https://youtu.be/lqjVGhzDz2U

[Andratch]

Cool,

i found this a issue for me, with another car i owned in the past. Once the oil got a bit old, ( length of time ) ie, more than 6 months, I would get the rattle start, This was a car that sat 5 days a week, so the mileage on the oil was low. Once i changed the oil, the rattle would disappear again. I figured it was just the quality of oil at the time, now reading this post has me thinking otherwise

Interesting. I will say, my oil is only about 3 months old and only has a few hundred miles on it - but a few of those miles includes a HPDE event. I still wouldn't say that's my problem here, but if all else fails an oil change is cheaper than taking off the timing chain cover.

I did replace my timing chain tensioner with a new one back over the winter because I didn't yet understand that the S54 is just a noisy engine in general, and so I was trying to eliminate a 'normal' noise by swapping what I now believe was a good, working tensioner with another new one. The shop called me on Friday to say that they took out the one I bought from FCP and replaced it again, and didn't hear the sound after 24 hours of sitting.....so, fingers crossed all this fuss was a faulty replacement part. I'm not overly confident, but I can't really see what else it could be.

[lemoose]

IMO If your behaves or sounds and differently after an oil change that is a very somber indicator that your oil change intervals are way too long.

[Andratch]

IMO If your behaves or sounds and differently after an oil change that is a very somber indicator that your oil change intervals are way too long.

My oil is only about 200 miles / 3 months old, though there was a HPDE in there. It’s LiquiMoly synthetic 10W60

[Slideways]

The factory CSL tune would do this 2-3 sec cold start rattle noise. The revs would pop up to near 2k before they immediately dropped back down to cold start idle. With the cold start map adjusted, it no longer does this rattle. Disabling cold start might be a good, easy test.

[ac427]

The factory CSL tune would do this 2-3 sec cold start rattle noise. The revs would pop up to near 2k before they immediately dropped back down to cold start idle. With the cold start map adjusted, it no longer does this rattle. Disabling cold start might be a good, easy test.

I wonder if they changed that on the later CSL tune. I have the CSL tune on mine and i'm pretty sure it doesn't raise initial revs to 2krpm.

[Andratch]

I got my car back.......no dice on the second tensioner replacement. Noise persists.

The shop noticed that there is a little rattle between 2-3k rpm, almost exactly like THIS and suggested maybe it's Vanos related. My car already has the Beisan upgraded oil pump disc, so I'm not sure what else from the Vanos could be making that noise....

I ran a snake camera down by the timing chain to see if I could see any obvious signs of guide damage, nothing there either. Honestly, everything looks like it's in tip top shape.

I think this started after a HPDE, so after the car spent a good amount of time at high rpm. I haven't done a valve/lifter adjustment, so i'm going to do that as preventative maintenance and see if that helps. Other than that, everything looks to be in fantastic shape.

[BL92]

I .

I think this started after a HPDE, so after the car spent a good amount of time at high rpm..

I believe the oil has broken down after all that high heat !

IMO If your behaves or sounds and differently after an oil change that is a very somber indicator that your oil change intervals are way too long.

I agree, Most Shops here Australia recommend an oil change ( 10,000ks ) 6200 miles or in 6 months, Which ever comes first

[Andratch]

I ordered BMW 10W60 M TwinPower Turbo Oil from FCP, and am planning to do an oil change over the weekend to see if that helps. At least it'll give me a chance to send off a sample of the old oil to Blackstone since that oil was added back in March after brand new rod bearings and then a HPDE in April.

[Slideways]

Here is a video of a DINAN car with 40k miles and it revs almost up to 2k RPM while making that cold start rattle sound:

And another car that only revs up to 1.5k RPM and does not have the rattle:

[Andratch]

Here is a video of a DINAN car with 40k miles and it revs almost up to 2k RPM while making that cold start rattle sound:

And another car that only revs up to 1.5k RPM and does not have the rattle:

unfortunately this isn’t my issue. I started the car today and it only revved to 1500rpm, still made the noise.

[Andratch]

Update: I’m fairly certain this is a VANOS related noise. While I do have a few Beisan parts, my VANOS unit itself is original - and when using a mechanic stethoscope, the noise is the loudest from the VANOS unit itself.

I’ll probably wait until the weather is a little cooler and bite the bullet on a replacement VANOS unit.

[Andratch]

I'm having these exact same symptoms, funnily enough, it only started happening AFTER I completed my top end rebuild. It has been making a rattling, knock sort of noise for 1-2 seconds upon a cold start, it's always in the morning when the car has sat overnight. Vanos has been upgraded to Beisan and had less than 500 miles on it at the time, so I knew it wasn't that but I too searched high and low for the source. Sounds like you found the culprit for me, I appreciate you updating this thread. Going to order an OEM piece and get to work, most likely upgrade the pulleys since I'll be in that general area anyway.

When you say your VANOS was upgraded to Beisan, do you mean it's a totally new unit? Or it was serviced? What all did you do?

[Andratch]

UPDATE:

Ok, next phase of the noise diagnosis starts today. I am re-rebuilding my VANOS unit.

When I purchased the car, one of the perks was that the VANOS was already "Done," and I can see evidence of that in the form of Beisan oil pump disc and exhaust side chain guide. But I have no idea what else was done. So, I'm going to throw in all the new gaskets and goodies and see if that helps. I'm not sure if the 'anti-rattle kit' is needed here, but we'll see.

I'll report back in a week or so with news.