Hey All,

Here's a new one, I've got a weird sound at idle, it's a sound like old tv shows used for ray guns or ufo's, it's a high pitched oscillating sound that cycles high and low. At startup I hear a sharp sound like the squeal of a dry bearing, but it goes away fast, then a slowly cycling sound that hops up a register, gets faster, and then I have ray gun noise. When I first heard it, it sounded like a home security system alarm going off near by. So far I've been unable to pinpoint it with a stethoscope. I'm stumped, any ideas?

thanks

 

Just some ideas

Serpentine belt
bearing going
maybe fan clutch
If it comes and goes at idle AC

 

It must be belt or bearing man. Not sure though.

 

Open up the hood and find it. How many miles do you have? Do you know if the water pump has been replaced yet? I had a similar noise per say, turned out the water pump was on its last leg.

 

do you have a digital camera? If so, shoot a video of it and throw it up on youtube for us to hear

 

Sorry for the lack of details, it's a 98, 5.9, 117,000 miles. Thanks for the suggestions, I checked them all out. Turns out there were lots of contributing factors to noise in general, just not the ufo sound. There was tensioner/idler pulley noise, replaced. The belt was due, replaced. The fan clutch was okay but not great, replaced. I ran it with the belt off and found that the sound continued for a few seconds after the motor stopped, but in a steady fashion instead of oscillating as it did while the engine was running. I started looking for a vacuum leak, and found the hose for the pcv valve had cracked, replaced that, but that didn't stop it. Just by chance, I bumped the hose going from the vent on the drivers side valve cover to the bib on the cold air intake, and the sound stopped. I tugged on the hose a bit and could then hear the vaccum sound from around the seal on the valve cover. Some weird combination of the vaccum plus the gap in the seal was creating the sound, which had gotten so loud that the guy across the street could hear it in his house, and asked me where the little green men were.

Anyway, it's too late today to get any new parts, but, I routed the hose to the cold air intake so that it doesn't have the same directional pressure on it and the sound is gone.

I replaced a bunch of stuff that either needed it or was getting close to needing it, it's running a little cooler now, so that I don't mind, and, at least it wasn't the water pump.

Thanks again

 

Glad to hear you got it fixed, goob job!