I just purchased an 05 G35 Coupe 6MT about a month ago. After about two weeks I noticed a semi loud clunk sound that happens right after turning over the engine. It only happens after the car has been sitting for sometime (usually in the morning on the way to work and in the evenings returning home). If I start once and restart soon after the clunk is gone. I turned off the radio and heating/air conditioner and it still happens. When the AC was on I heard the clunk and then the AC click on. I called the dealer and they said it was the ABS self test feature which states in the owner's manual "When the self-test occurs, you may hear a clunk noise." Just wondering if anyone else has the same thing or if the ABS story they gave me is a bunch of BS.

 

Yes the ABS makes noises when initializing, also the timing chain can make a strange noise at start-up in the morning. As long as it lasts only a second or 2, you're good to go.
C.

 

Sounds like the ABS system. Mine sounds like a fart, not a clunk. I think you are OK.

 

Yeah I have the same thing. Infiniti told me not to worry about it. So do you guys, so I'm pretty confident everything is okay.