dinosaur12

The wife's 2002 Infiniti i35 (stock with 135k) has developed a noise that happens when the engine is cold. After about 5-10miles the sound will subside or maybe its just not as noticeable. The sound seems to come from the right (passenger) side of the engine bay and will come/go depending on throttle position and engine load. Under light load and throttle is when the noise will be most noticeable. If the noise is happening and I add about 10% more throttle input it will stop.

I want to say the sound is coming from the intake side but I am not 100%. Its NOT the normal rattle/ping sound that I see posted all the time on these forms. It sounds kind of like a garbage disposal running. Its pretty loud, can hear it over the radio.

Does this engine have some sort of variable length intake runners? Any sort of variable anything that would cause this type of noise? I am really hoping this is a common issue and is easily fixable.

Thanks for any help/input you guys/gals might have

Scottwax

iTrader: (8)

Transmission is on that side as well, could be an issue with that since it goes away as the car warms up.

nelledge

iTrader: (6)

You have referenced both sides of the engine bay. Is it passenger or driver side? Here's a shot in the dark with the minimal information: failing pulley? Have you checked the tension on the belts?

dinosaur12

Sorry for the confusion. When I say intake side I was trying to suggest that it was from the air going into the cylinders rather then coming out of the cylinders. Was not trying to say it was coming from the air filter box, I am more thinking the intake manifold (this would be passenger side).

I might have to put this thread on hold and see if I can get a video recorder and post the video on here. Its really hard to diagnose something you can not hear/see. I was really hoping this was ganna be a simple "known" problem.

I will have a look at the belts but not going to hold my breath. If it was the belts they should be doing it all the time. If not doing it all the time should be doing it more with higher RPM's and more load, thats not the case.

Thanks for your help/suggestions.

pkrainert

My car makes a weird sound like that I am pretty sure mine is the starter though becuase it only happens for about 5 seconds after I start it. I think its not retracting after it starts.

nelledge

iTrader: (6)

No problem. I just wanted to clarify. As far as the belt tension, I was asking more as a way to check the tensioner not the belts themselves. It sounds like you have a loose pulley. Maybe the alt, ps pump, or tensioner bearing.

N2003TE

iTrader: (-1)

Is there an aftermarket intake on it? Or NWP spacers? I know on mines I have a whistle that only happens at a certain throttle position. Hopefully that's it, and if so its nothing to worry about.

pinellas50

Given the limited info my first thought would also be something with the accessories. I just went through something similar with my 01. I took the main belt off and the noise went away. Turned out to be the alternator.