Guys,

I'm really hoping someone here can shed some light on what my potential issue is. I recently purchased a 2008 Dodge Ram quad cab 5.7 automatic in what seems to be great shape. The truck drives fine, shifts great, has no leaks, etc.

The one issue I've discovered (and has me worried) is that it has a very pronounced "whine/cricket chirping" sound at idle, in any gear (Park, Neutral, reverse and any forward gear). It sounds like a large box of steroid-infused crickets. It seems to be in sync with the cams rotating or the crank.

It does not do it when the truck is completely cold. When I start it in the morning the truck sounds "normal". As soon as I drive around my block it will start the "cricket racket" and is very pronounced especially when beside a building or another vehicle. It will not go away until the truck is completely cooled down. It gets louder as the truck gets warmer and then levels out once up to temp.

I've taken the serpentine belt completely off to rule out any rotating accessory issues. The problem remains with the belt off. I've also tried taking the oil dipstick and oil fill cap off to relieve pressure in the crank in case it is the sound of air seeping past a seal or a bad PCV.

Crawling under the truck and listening around, it's hard to pinpoint where exactly the noise is coming from due to all the racket. It seems loudest when I get around the oil pan/transmission. But it could also be coming from just up above, like it could be cam noise. I just can't be certain.

I've had the local Dodge dealership listen to it, get confused about it's origin, and then suggest a "dry rear main seal that will eventually need replaced". Taking it to the local transmission shop of repute, I was told that "it's not the transmission making that noise". Both places have told me to just drive around with it like this, that it's fine...

Here is a youtube video I found of another Hemi vehicle that sounds exactly like the whine I'm hearing, except the video sound doesn't do it justice (sounds much louder in real life). It's that high pitched whine you can hear in the background. The rumbly exhaust in the video almost drowns out the sound I'm referring to.


Hoping you folks can steer me in a direction that doesn't include me losing my mind. Hard to correct a problem when every "expert" that looks at it seems to think it's unusual, but not really a concern.

Thanks in advance.

 

Hard to tell from that video but try removing the belt and see if it stops. Possibly the fan or a pulley. Don't run it long with the belt off.

Somewhat sounds like an air whine into the intake also. Maybe try removing everything up to the throttle body?

 

"I've taken the serpentine belt completely off to rule out any rotating accessory issues. The problem remains with the belt off. I've also tried taking the oil dipstick and oil fill cap off to relieve pressure in the crank in case it is the sound of air seeping past a seal or a bad PCV."

I ran the truck for 2-3 minutes with the belt completely removed, no accessories spinning, just the crank pulley, and the sound was still there. Definitely not a tensioner, alternator, water pump, etc.

 

Sorry, I skipped over the part where you mentioned that... ;(

I've heard the transmission whine a bit if you rev it up without any fluid in it (Had a bad filter gasket in the tranny before) but nothing like the video.

Edit: If the sound is similar to the video I guess a good place to look would be at the CAM, I think you've already found your next area to look at.

 

is it a rythmic whine like its related to a certain point of rotation or is it constant?

 

It seems to be rhythmic, it's not a constant whine like a pump impeller would cause.

 

You may have a bad lifter, theres really too much to guess at without hearing it in person.

 

Unfortunately I've had it at three different shops now (Dodge dealer, a transmission shop, and another shop that does engines and transmissions) and no one can tell me what it is.

Here is a video I just made of the sound it is making. It is quite obvious in my video.

 

This is probably a bad example (I think the engine sounds like crap to begin with) but it sounds similar to this IMO: http://www.k20a.org/forum/showthread.php?t=83120

It sounds like a metal whine to me. How many miles are on the truck and do you know what service has been done to it at all?

 

I don't know how old this blog is but I've had a shower problem with my 08 Dodge ram 1500 5.7 l with the noise was coming from the back while the alternator. I used to screw driver and put my ear to it and tapped all over the place to see if I can pinpoint it and that's where it was coming from so I replaced my alternator which took the noise away but I have no idea what the problem was. But using this stethoscopes or long screwdriver usually helps pinpoint it I imagine there's some type of buildup inside the alternator and coming in contact with the alternator spinning within or towards the back. My plans are to try to clean out the alternator and possibly buy a bracket so I can install both alternators. Ironically the water pump rubber went bad made the fan started wobbling it actually started hitting my air conditioning lines it started wobbling so bad at first I thought maybe the rubber seal of the water pump was what was making the noise but I have to replace the water pump the noise was still there and then I tracked it down to the back of the alternator. Good luck if you haven't already fixed it