i have a 2005 350z , with about 66k miles on it... whenever i will start my car, i will hear loud noise that i don't know exactly where it's coming from . But i noticed that it always goes away after the engine is warmed up, and wont start again till the car hasn't been on for about 3 or 4 hours.

http://www.youtube.com/watch?v=aWIbZaigQWI

The Second Video shows my TRUST exhaust sound that i think it's not normal ( when i release the gas pedal ). i just bought the car few weeks ago, So i can not determine if it's OK or no .

http://www.youtube.com/watch?v=SHkDIq6uWUU

Any ideas ???

 

Exhaust noise is a variable of a hiss, you can check for leaks, but I would guess the car is running HFC by the sound of that exhaust (or lack there of, heh)... do you know whether it is not?

Regardless, check for leaks... first noise, that's up to someone else, very interesting however.

 

sounds like rod knock... not good..

 

not a good noise in the 1st vid..but idk hard to tell, def. sounds like its in the motor...2nd vid sounds like a exhaust leak or just crappy exhaust sound, ive never heard that exhaust and if u have test pipes or maybe even high flow cats it may be normal

 

Agree.

Video #1: I listened several times and am stumped:

a. This is a heatshield under the car vibrating?
b. The motor is driving something (power steering pump) and the bearings in that component are bad.

Video #2: Sounds OK to me.

 

Thanks for the inputs, this morning i noticed that the noise is more louder at the drivers side, does it make any difference?

 

I like the graphics on your car.

It does kinda sound like a knock in the first video.
Video 2 sounds like it's about to backfire.

Something is causing a bad fuel/air mixture which might be causing both problems.

 

i contacted nissan dealer today asking him to check for any leaks in the exhaust, but he refused to check the car ( Since the exhaust is aftermarket ) . will the diagnosis codes be able to tell where exactly the error ? if so, i will get it checked tomorrow . The car is running O.K & no SES light has came on but it's still my doubts that there's something wrong ...

 

So, i still have the problems unsolved. i checked the exhaust system & found that my OEM Y-Pipe doesn't look good . i couldn't detect any leaks while a friend of mine was accelerating . i uploaded some pictures, may be someone will be able to judge if it could be the Y-Pipe !!!


Thanks...