Hi Fellow G37 owners,

This is my first post and I apologize if this is posted in the wrong place. I'm having this strange squeaking/rattling noise (as attached) in my engine bay. I'm hoping to get some wisdom from the community because apparently, my mechanic has no idea what he's doing. Here are the symptoms and what I've done so far:

(0) The noise comes up only when the car starts from cold.
(0.1) Sometimes when the car was left to cool for half an hour, when the engine is still warm, the noise still comes up.

(1) The engine bay gave a continuous squeaking/rattling noise when I make a big right turn and throttle.
(1.1) If I turn the steering wheel clockwise when the car is still (e.g. parked), no noise.
(1.2) If I turn the steering wheel clockwise just a little (e.g. to change lanes), no noise.
(1.3) If I turn the steering wheel clockwise all the way to the end, but move backwards slowly (e.g., back out of my garage), no noise.
(1.4) If I turn the steering wheel counter-clockwise, no noise at all.

(2) The noise is continuous if I keep going straight after the turn, or make another right turn.
(2.1) The noise sometimes disappears (about 70% of the time) when I later turn left.

(3) I replaced the driving belt, the tensioner, the three idlers.
(3.1) I think the noise reduced a little bit, but it still comes up when I make a right turn

(4) The noise came from the left-hand side of the engine bay (the steering fluid reservoir side).
(4.1) My guess is that something else caused the noise and put a burden on the belt

(5) I have enough steering fluid in the reservoir.

This is giving me a hard time since I don't want to damage my car, but have no idea whether the noise is benign or can indicate something more serious. Any inputs are well appreciated, and I hope your G37 will never have this problem.

 

How many miles do you have on it and what year? Auto or 6mt? Any leaks anywhere in the engine bay or ground?

That noise is weird! I don't think I've heard that before (except maybe something similar to the movie Mission to Mars lol). What was the condition of the car when you took that video, cold start? Was this after you replaced all the belts, idlers, tensioners, etc.?

When the issue occurs or it disappears you mentioned it occurs during steering which leads me to believe you have something going on with your power steering system. Maybe the pump going bad? Is the rack leaking? Does your steering feel feel any different or off?

 

Thanks for the reply man I appreciate it. The G37 is auto and got 65K miles. As far as I can tell there's no leak and all fluids are normal (no warning lights).

Yeah the car got cold start when I took the video, and it was after all the belt replacement. My suspicion is also the power steering, the pump especially. I'm going to a dealer tomorrow to check things out because these kinds of noises can indicate very serious problem with steering. I'll post updates tomorrow.

 

No problem man. Interested to hear what they say.