Well now its making some sort of humming noise coming from the engine somewhere. Not the transmission. The car idles and revs good. No smoke, sputtering, or knocking noises. Just a light humming noise that speeds up as the engine revs. First I thought maybe it was the AC compressor, but when I turn on the AC it doesnt even affect the noise. I put my ear next to the motor and it sounds like its either coming from the intake manifold, or the front timing cover. Somewhere in that area. I took the oil cap off when it was running and it went "pssscchhh", like it had some air pressure built up. Dont know if thats normal or not. Sound didnt get louder so im assuming its not coming from that head. Only modifications I have done to the valve covers is I replaced the stock heated pcv valve with a non-heated 03 cobra one. Has a fairly new belt tensioner and belt. I just cant seem to figure out what it is. The only other thing I can think of is maybe the water pump or power steering but they seem to be working fine. Anyone had this noise before? The car has 130,000 miles believe it or not. 75% highway miles. I have another engine waiting for it but wanted to build it up before I dropped it in....plus I just moved so I really dont have the cash to take it to the dealer.

 

ok I used a car stethescope (aka tire iron) and put it to my ear while holding the other end to various parts of the motor. Heads, bottom end, intake, water pump, power steering pump, and ac compressor are all smooth and quiet sounding. The only actual noise I got was from the alternator. It sounded like that MAY be the cause of this humming noise. That alternator is not the original one. i swapped it from my other motor because the one I had on there was getting rusty on the inside. I wont worry about it for now, I may swap the other one back on there whenever I swap the s/c pulley if I ever do. Then listen to see if the noise is still there. You can barely hear it. Others say they hear nothing different but I drive this thing everyday and I can tell its a new sound. All i was really worried about was the heads and bottom end, but they sound really good so its ok.

 

There are needle bearings in the alternator that sometimes start to fail and make a noise similar to a power steering pump whine. Maybe thats it ? Just check the pulley for side play.

 

will do...