I've posted this question on youtube and in the 3rd gen forum and have gotten ideas of everything from a blown head gasket to an exhaust leak to a broken valve spring. What is this weird sound coming from my engine?

Here's the link to listen to it-
http://www.youtube.com/watch?v=gNX3-56yI-s

I hear it almost every time I start driving the car even if the engine is relatively warm. The sound follows the rpms, so when the rpms are low the whistling sound is slower and lower pitched and when the rpms climb higher the sound becomes higher pitched and whistles faster. The sound is coming from the passenger side of the engine somewhere near the back of the engine closer to the firewall.

I'll hear the sound usually for 4 or 5 minutes after starting up the car. I hear it when I am in gear and at low rpms. As the rpms climb to about 2000 the sound will dissapear. Then I'll shift at 2500 or so and I'll hear the sound again in the new gear as the rpms move up until I get to 2000 rpms again and it dissapears again. I hear it at idle sometimes also, soon after starting up the car.

What I know: It's NOT the VTC's, I know what that sounds like. I thought it could be the new pcv valve I put in around the time I started hearing the sound (about a year ago). This is a pretty loud sound, though, and I don't think it could be coming from the pcv valve. I did change the pcv valve again to check if that would get rid of the sound, and it didn't. The new pcv valve I used is the same brand of pcv valve I put in a year ago, so maybe it's a bad brand (Beck-Arnley)? Also, the sound does not affect the cars performance in any way, it's just an annoying sound.

Could the sound be a leak in the exhaust manifold, maybe dissapearing when the engine is warm (though I still hear the sound after starting up the car when it's been sitting for only a half hour or so)? Could it be the bad brand of pcv valve? Maybe a broken valve spring like one person guessed?

Thanks for all your help!

 

I seriously doubt it's the pcv valve. Exhaust doubtful again,,its more of a whooshh not screeching sound. I'm unfamiliar of 3rd gens but that sounds like a bad/broken upper guide 4 the timing chain in 240sx. I would say it's internal and you would have to pop off the valve cover to inspect.

 

i made my friend's car sound like that..

i put that little whistle thing in his exhaust...

 

Maybe a rod bearing? That sound is pretty new to me