I have a 2012 G37x sedan (24,000 miles), and for the first 30 seconds or so of warm up (its winter where I live), there is a bit of a rattly sound from the center of the car that almost sounds like something is loose and like a bit of a leak. After the 30 seconds, while the car is still at fast idle, the noise subsides.

Is this normal? If it starts and remains noisy I'd be convinced there is something wrong, but am confused that it consistently goes away after 30 seconds.

Thanks

 

normal

 

bro my G37 coupe does the same thing its so loud too its almost emberassing and does it everytime my car sits parked for a long time and after that long time ill start it and itll make that loud noise..... its something to do with the heat shield or something is loose with the exhaust. when i was getting my tires flipped and i mentioned it to him while the car was on the lift (my friend who is a GTR specialist with nissan that i trust very much knew what the sound was instantly) but thats for my coupe. hope it helps.

 

Normal.

I like it.

 

^different issue, yours seems to occur after the car is running for a while, OP claims the noise is only on cold start and dies down as the engine warms.

When I bought my car (new), I thought something was wrong with it too. Almost sounded like a diesel at a cold start. But supposedly this is normal for the 3.7L VQ engine, something with the injectors or something??

Think you'll get used to it.

 

Yeah. The VQ37 isn't the most refined sounding engine on cold start. Oh well. I wish the sedan's exhaust was louder to cover all the other noise.

 

The noise has to do with the variable valve timing on a cold start. The noise is coming from the exhaust valves. Once the engine and the computer have a sec or 30 to get in sync the noise goes away and your off to the races!

 

Ok, so its basically normal.
Not ideal but it is what it is.
Thanks for all the replies.

 

Thought something was weird with my car too but nice to hear that it is common

 

I wish it didn't go away when it warmed up :P

 

I'll never forget the day I test drove the car, and it made that sound on startup. Initially I looked like this: , but then I realized it was pretty awesome. It's like waking a sleeping beast that is angry until it has had a chance to 'warm up' to its surroundings

 

Lots of people ask this question, myself included a few years ago. I even made a WTF video, LOL.

 

My car kinda ticks like that after driving, if i'm not in gear, I dont think mines normal, I'll have to make a video;