Anytime I have been running at full operating temperature for a few minutes, and then slow back down (like exiting the freeway to access my neighborhood), I get a loud/annoying buzz from the motor whenever I cross the 1300 RPM zone. Either revving up or down, it buzzes for just a second then then it's gone. If I hold it right at 1300, it buzzes constantly. Now, it won't do this when it's (the motor) cold; when it's cold it makes a hissing sound right there, almost like a tire going flat (definetly not the turbo...). When I got home and was checking it out, the sound is coming from right near the alternator/oil filter. It sounds kind of like a trading card in a bicylce wheel, but really really fast. Anyone else having this phenom??? ???

 

Get someone to hold it at 1300 and start grabbing stuff until the noise goes away. If this does not work remove serpentine belt and see if this noise is acc vibration induced. May be a line grounding out, or a bracket loose and causing a resonation at that rpm.

 

I have tried to move everything I can get my hands on when it's buzzing, and there isn't a darn thing loose... Thanks for the advise though. I will try the serpentine belt idea this weekend and report my findings. Anyone else have any ideas???

 

I was thinking something like that is very possible, as that is RIGHT where the sound is coming from. However, I don't think the filters have a bypass/check valve in them... However, I do believe there is one in the casting the filter screws into, hiddin by the plug seen from the top. I'm not sure on this, but it's all I have to go on... I will change the oil this weekend too, and see if the noise goes away with a fresh filter.