Hey guys,

I just noticed something about my car ('03 SB Z Touring - 23k mi.). I thought I'd stop by here & get some advice before running off the dealership with my car & money. Let me know your thoughts:

I live in Atlanta & we have had some pretty cold weather (30-50 degrees) here lately. I've noticed that @ idle my car sounds louder, but only inside the car. The car has normally been quiet & smooth sounding, but now I get a bit more of a hum when it idles & at low RPMs. It sounds like it is coming from the passenger side of the car. When I rev the engine or while I'm driving I don't notice it & nothing sounds loose. I figure I would hear if something was loose because I go over speed bumps (slowly!) every day. Is anyone have an idea if this is normal for cold temps? Do I possibly have a leak? I need an oil change soon (5k on synth oil currently), but I wouldn't think that would have anything to with my car idling louder, would it?

Please advise on whether something could be going wrong or I'm just being paranoid!!!!!

Thanks!
Solo

 

I have the same issue. I only hear it inside at 750-ish rpm (i.e. warm idle). It sounds like a constant rumble, like construction equipment in the distance. It is louder near the passenger floorboard.

I first noticed it after my oil change last week. I went back to the dealer to check the underengine cover and they say it is tight.

It's starting to bother me because I have a road trip this weekend.

Btw, I'm all stock.

 

maybe bad/weak gas???

https://my350z.com/forum/showthread....ght=idle+noise

 

next time you hear it, hold the clutch pedal in all the way, and see if it stops.. if it does, your car is perfectly fine

 

ya **** that..... thats what i thought.. then b4 my warranty went out i had them check the noise just incase something was up, and they called me telling me im getting a new tranny

 

It's not the clutch or flywheel noise. Take your finger and lightly tap your desk 2-3 times per second. That's what it sounds like.

 

my exhaust also lets out little mini exhaust farts, its always done that, since new, only when warm

could be it?

 

I've heard the "mini-farts" near the exhaust tips, but this is a steady tapping noise, louder when the car warms up and idles at 750-ish rpm. If I rev the engine gently, the sound disappears and the engine sounds normal. I'm thinking it is a sympathetic resonance of something (maybe the cats?) under the floorboard area.

Besides myself, two other people have noticed the sound also, so it's not my imagination!

 

maybe the sound is resonated inside the cabin?

 

I bought a stethoscope at the auto parts store. I tried it out this morning at the gas station where I went to fill-up. I'm sure that was a funny sight - some dude wearing a stethoscope giving his car a check-up! "Cough, please."

Anyway, I scoped various engine parts and I have to say the engine is veeery smooth running and sounding.

I scoped the frame and other parts and everything sounded fine. I could not reach under the car to check the exhaust system, however.

Next, I went inside the car and scoped the floorboard and definitely heard a vibration. I'm guessing something under the floorboard (exhaust maybe?) is vibrating and bumping a body part??

Could the exhaust itself be noisy? Perhaps there is a small leak in the system, maybe a bad gasket? It seems unlikely, though, because my car has only 7500 miles on it.

 

Hey, I have the exact same noise. Sounded to me like the slapping of a loose timing belt. Kicks in when idel falls below 750rpm. Gently touch the throttle and idle goes up to 750rpm, noise goes away for the duration until the light turns green. It's loud enough to be barely heard over the audio system. I have several times paused the CD to listen to the rapping of the motor at idle. I have the 5AT with Stillen engine damping strut.

Rich

 

pgh2atl,
Same problem here. It's from the passenger floorboard; a buzz/rumble noise that can only really be heard at startup and at idle. It also only seems to occur when the car is warmed up. Yesterday the dealership tightened a heat sheild thinking it would fix the problem. It did not, so I'm taking it back to the dealership Friday. I'll let you know what they find.

 

if the noise goes away when you push the clutch in then its your throwout bearing going bad.

 

No, the clutch has no affect, neither does gear selection. The HVAC on/off does not affect it. So, it must be an engine noise...

 

AHAHAHAHAAAA!!! mini exhaust farts....lol...i lost my drink when i read that!!! lol!!

 

I listened to the noise today in the light of your suggestion, and I agree that it sounds like a thin metal plate vibrating against its screws, just beneath the transmission. I have the automatic tranny, so not a clutch issue.

 

My Z's just recently developed the same thing. sounds exactly like that tapping your finger against the desk comment and its only audible at idle rpms. I'm thinking it may be associated with my crawford HFC's rubbing against a heatshield as that is a known problem. however when I installed them, I still had lots of clearance. I guess they may have shifted due to me scrapping the bottom of my Z on my driveway a lot. plz post what the dealership finds, although I have very little faith in many nissan service depts.

 

I Have Noticed The Idle Engine Noise That You Guys Have Explained, Can Anyone Tell Me If They Have Found The Cause Of The Problem, Because My Z Is In The Garage And They Dont Know What It Is That Causing It,
Any Ideas
Thanks

 

I have transmission noise also, going to check again tomorrow morning. I have 13.5K miles on my Z.

 

[QUOTE=bimmersandZs]pgh2atl,
Same problem here. It's from the passenger floorboard; a buzz/rumble noise that can only really be heard at startup and at idle. It also only seems to occur when the car is warmed up. Yesterday the dealership tightened a heat sheild thinking it would fix the prob