VTC intake camshaft sprocket. I'll explain more when I have time. I am very aware that it is not the ABS, this is a component of your timing system and is located on the front of the engine, in the tear drop shaped cover or the double circle cover for rev-up. Look it up.

I'll see if I can post the TSB later tonight, it's for a VQ35DE maxima but it applies to the G35 as well. Same engine. Again, I am 110% sure this is your problem.

 

i look forward to your posting ,

thankyou,

and if possible could you ball park the pricing for this ?

 

I can't find the TSB unfortunately. I had a noise in my engine and spend months learning about every single component. You're describing the exact symptoms, I'm very sure it's the problem. The sprocket has a small leak and is basically is not holding oil pressure in the gear at start-up, and grinding the internal components of the sprocket.

Ballpark about $1500-2000 from the dealership. The part alone is about $400. An independent VQ mechanic might do it for $800 or so.

You'll need to use an automotive stethoscope and have someone start the engine to determine which one is causing the noise. The part that's defective is one of the large sprockets with the 4 bolts on it.


Pic taken from this thread.
http://my350z.com/forum/engine-drive...ing-chain.html

 

damn if this is for sure the problem im going to buy after market warranty and get it done at the dealers. Ill call my friend who works at infiniti if he can check out my car tommorow.


thanks for your help , ill come back to reply on the news !

 

Don't let someone at the dealer, even if he is your friend, look at it before you get your warranty. If the warranty company you choose can prove the issue existed before you bought the warranty they can/will deny the claim.

 

Are we sure this isn't the typical timing chain tensioner rattle? It runs on oil pressure to put tension on the timing chain and the noise is the chain flopping around until pressure builds up.

Take from that same thread, this part is easier/cheaper to replace:



Being an 03, the chain guides can also come loose, but then you'd have chain noise all the time, so for now I'd say it's just the tensioner.

 

I have the same grinding noise on a cold start up but it doesn't always happen, sometimes its louder and lasts longer than other times too.
^does the timing chain tensioner rattle occur while driving or during start up like previously stated by OP?
04 5AT btw

 

UPDATE

i called my friend who works down at Tustin Infiniti and he said that its most likely the chain rattling and this is caused by low oil levels in the engine. I remember i did my oil change and it was about a quart low which is a first for me. He told me to change it every 3500 miles , ive been doing it at 4500. But im going to have him take a stethoscope to see if thats the problem about the CVT sprocket. He also said its a common problem with the 1st Gen G35s to have this rattle / grinding noise on cold starts.

 

for me it only happens after a cold start up then it goes away till the next cold start

 

I took the below video when my car was rattling at cold start up. I also had a faint rattling noise at a specific RPM range. When I took it into the dealership they kept telling me that they couldn't duplicate the issue so I took this video of a cold start.


Once they reviewed the video and sent it off to the regional "super" tech, they took the timing chain covers off and found that one of the passages was partially blocked with RTV from where Infiniti replaced the long block under warranty because of the Oil Consumption TSB. While they were in there, they also replaced the CVT gears. This solved the faint rattle that I had and also the cold start rattle that I was having but only for a few months. It's now only rattling a tiny bit at start up. My check engine light was also on and I had replaced both cam position sensors and the crank position sensor. Once they fixed the blocked passage and the CVT gears, the light went off and hasn't been on.

While I was driving the loaner G37 and G25 I also noticed that there was a very slight rattle at start up, until the oil pressure was up. These loaner vehicles had under 5000 miles so I take this slight start up rattle now as normal.

 

sorry, have to post again b/c that last one was post # 666

 

^Not quite

 

I say quite true it its for seconds.Just dry starting.

 

That video is a perfect representation of the rattle I have at cold start but there are days where its louder and lasts a second or two longer :/

 

Just watched the video. Relax.