Topic: 3.0 V6 engine noise when cold

[94runner]

I replaced the valve covers a couple weeks ago and i've got a strange sound coming from the engine bay when i start it up.
-The sound starts when i fire up the truck and last a minute or two, then aburptly goes away.
-It only happens when the truck is cold.
-If i blip the gas, the noise will go away for a split second.
-The sound is much louder in the cab. I can barely hear the noise if i try to listen under the hood.
-If i stand on the brakes let the clutch out (lowering the RPM's to just above stalling) the sound will go away until i push the clutch back and the RPM's go back up.
-The truck drives fine whether or not the sound is there.

Can somebody please help me diagnose this sound.  video of said sound below

http://s306.photobucket.com/albums/nn273/ninety4runner/yota%20front%20axle/?action=view&current=P6200086.mp4

[94runner [OP]]

bump. still haven't figured this out..... sounds like a bearing, but the sound goes away after ~1 min.

[94runner [OP]]

bump. i'll try and get some more/better video up soon. Still haven't figured this out. any ideas?

[floorrunner]

so the noise was not there before the valve cover gasket change?

[junya92toy]

WHats it sound like?

[94runner [OP]]

so the noise was not there before the valve cover gasket change?

No, it was not. I'm not really sure the valve cover change cause it though. I think the noise just happen to occur after i changed the covers.

WHats it sound like?

There's a video in the original post

[junya92toy]

Its too quiet, I was told you want a little valve noise on them .

[94runner [OP]]

it's not valve noise, i know what that sounds like.
it sounds like it could be a bearing. i'll try and get some better video.

[junya92toy]

I never said it was valve noise. Im saying it has lack of valve noise.

[superyota]

from the discription you gave, i would lean towards saying it's a rod knock.

[94runner [OP]]

from the discription you gave, i would lean towards saying it's a rod knock.

would a rod knock go away after a minute(after it warms up) though?

[junya92toy]

Maybe at first but usually  no. try taking all the accessory belts off.

[Bobby Hunter]

might be the pair valve, it could come on with the rpms so high, plug the vac lines for the pair valve see if it changes anything

[superyota]

a rod knock would become less noisy once the motor fires up and oil gets to whichever bearing/rod is knocking.  and it would be more noisy when cold and oil is thicker, taking longer to makes its way through the motor.  but usually, it would quiet down after a few seconds, not a few minutes.  also, if you "feather" the throttle, you can usually hear it come back on throttle up if its a rod knock.  not sure if that helps any, but it's my 

[junya92toy]

If the bearing is bad enough, no amount of oil will help

[94runner [OP]]

Maybe at first but usually  no. try taking all the accessory belts off.

i'll try this. thanks.

a rod knock would become less noisy once the motor fires up and oil gets to whichever bearing/rod is knocking.  and it would be more noisy when cold and oil is thicker, taking longer to makes its way through the motor.  but usually, it would quiet down after a few seconds, not a few minutes.

This makes sense to me.

also, if you "feather" the throttle, you can usually hear it come back on throttle up if its a rod knock.  not sure if that helps any, but it's my  

can you elaborate on this some more? if i "blip" the throttle the noise will go away for a split second but then will come back. Again, this lasts for a probably a minute if i just turn the truck on and let it idle, it will just all of a sudden go away, it doesn't get quieter or anything like that, it stops making the noise abruptly.

I hear what you guys are saying about it being a rod knock, but i guess i'm just not convinced yet because it really doesn't sound like the traditional rod knock sound. it almost sounds like it's more of a "whirling" sound that you would hearing from a bearing. I'll try to post up a better video on friday.

Thanks for the help.

[Bobby Hunter]

Pair valve disconnect the the vac lines