Does anyone know what is causing this noise? It’s become louder over the past 2 weeks, it only occurs on cold starts. It happens as you hear in the video and it disappears after wards. Could it be a piston slap? Timing chain? What do you guys think.

 

Post the video on youtube and put the link here.

 

Probably timing components if it is only at startup.

 

What are the chances of it being the chain itself vs the tensioners or lifters? I plan in doing this job myself since mechanics are quoting around 1,500 for this job. Most of the threads I find here are guys when they still had their warranty on the car.
2004 G35 coupe 93K miles, stock.

 

If it actually is timing related, it would be best to replace everything while it is opened up. Timing chains, tensioner, chain guides...etc. There are vendors on here that sell replacement kits that come with everything.

 

Did you end up solving this issue? My car recently started making this same 1-2 second rattle on a cold start. Based on research I have done it seems like either the timing chain tensioner or the VTC sprocket. If it is the tensioner I believe it can be accessed and changed via a small window.