Hello.
I have a VQ35 and it seems that i get a rattle, more like a knock when i start up. Ive noticed this happen when its hot outside (100+ F) and the engine is warm. Sound like when you change the oil and put a new filter in and you get that initial knocking rattle noise for a fraction of a second while the oil pressure builds up.

Anyone else run into such issue before? Can't be the tensioners/chains, all replaced by me. Using mobile 1 5W-30 synthetic. Have like 1K miles on the oil. Oil level at full.
Il try to catch a video of this.

 

Switch to 10W/40 for summer.

 

Yeah i might do that if this keeps happening.

 

sounds like timing chain rattle, try swapping to a heavier weight oil

 

I have the same thing this summer on my 2000 I30. I posted it a few weeks ago over at the 5th gen section, but did not get a single response.

I have also been using the same oil as you but have been using it for years and never had this issue before.

After reading around the web, some suggested (other cars and forums) that it could be a fuel delivery issue or fuel leaking from the injectors when off.

Other sites have discussed all types of rough starts that have been cured with seafoam

So, three days ago I added 2 bottles of Seafoam into a full tank of gas, and so far the issue has not happened. But, I need a few more days to be sure.

 

Nope, everything has been replaced when regarding timing chain components.

Ive already ran some seafoam in the tank couple months ago, but it was only 1/3 of the bottle.

 

So far so good after putting 2 bottles in a full tank at the same time, but will have a better idea after this weekend if this is the fix