ok..here is the issue i have..i have a 2004 g35 coupe..and my issue is....
it started about 2 weeks ago..when i start my car up (not all the time..happened about 4-5 times alrdy)..usally in the morning..or when the motor is kinda cold still..it cranks and fires but makes this werid *** crazy noise..kinda sounds like if u have a chain and bang them together..kinda like this cluncking noise coming from the motor...it last for about 1-2 second..but it sounds nasty..thats the best way i can explain it..im going to bring it to the dealer but..i was just wondering..has anyone ever had a problem like this? so i can find a better way to explain to the dealer wtf i hear..but it sounds NASTY..i am going to try and record the sound w/ my camcorder and post it up..but its going to be hard cuz it doesnt happen all the time...but man it sounds nasty..thanks

 

yeah i have the same noise...it's still uncertain and i haven't been able to get a solid answer. Some people say it's the exhaust or heat shields rattling, some people say it's the timing chain, and others had different noises confused with the "chain noise"

IMO...i'm begginning to think that it's indeed the timing chain but that just my wild guess. I agree that it sounds terrible and really takes away from the VQ exhaust sound. But here, check this out...

https://g35driver.com/forums/engine-drivetrain-forced-induction/133867-chain-dragging-noise.html

 

but i only hear it at start up.

 

I have the same sound too. It doesn't happen all of the time AND only happens when the car has been sitting overnight. I pretty much igonore it now chalking it up to being a normal noise.

This is the best explanation that I found. I know numerous members have said this but I'll quote DaveB since I found his post first:

 

When I start mine it doesnt sound like chains, but rather a bumb. It is only right after the starter engages the flywheels for a SPLIT SECOND and then its gone. I agree though, i have dismissed it as being a normal sound and I have convinced myself that it came from the factory like that.

 

I have an 04' G35 also..... I have the same prob. I broght it back to the dealership and they said theres nothing they can do about it....... It click,clonks until the car warms up, its really low sound though. I'm used to hearing it now. My car still runs like a champ thats all that matters!!.

 

i get it too. first thing in the morning and it has to be cold outside, like 40 or lower and it only does it for a few seconds then goes away. to me it sounds like the idler bearing or a bearing that is driven by the belt.it doesnt get cold much where i live so i dont care much.

 

its rod knock, my brand new engine replaced under oil consumption made that sound and seized up at 300 miles. They immediately replaced my engine again...see the video below!


F the VQ's known problems and infiniti wont reconize it!

 

it is not rod knock. the top end of the engine is dry and the valves are tapping. when the oil circulates (usually within 5-10 seconds) the valves have enough oil to be lubricated.

i cant say for sure what the absolute source of your valve knock comes from, but i would say most likely that you are using an oil filter that does not have a check valve. the check valve keeps the oil from draining back into your oil pan from top half of your engine. even with proper filters that have a check valve, oil will ultimately drain into the pan if you do not start your car fairly frequently, meaning at least once a week.

for those of you who are in cold weather, even though you may have oil in the upper end of the engine, the oil may be too cold, therefore thick to circulate immediately. lots of guys use 0w-30 during the winter to try and help with this. for those of you who don't know, the first half of the oil weight designate cold viscosity and the second is the hot viscosity.

anyway, this may be the cause.

 

Most of the complaints are centered around the metal timing chain. Quite a common complaint for our engines....

I've never experienced it constantly, only once in a great while when my car was not garaged in the winter months......