Yes, it is a fast buzzing sound. I've only had the car a few days, so I haven't changed the oil yet (but the oil looks new on the dipstick). I'll give that a try though.
But it doesn't really sound like lifters to me, for two reasons:
1. While the buzzing seems to be coming from the engine compartment, it doesn't appear to be coming from the engine itself. The buzzing has a clattering characteristic that makes it seem to be coming from some other component.
2. Also, the buzzing ceases very suddenly (it doesn't taper off). In my (limited) experience, lifter noise tapers off as the lifters pressurize.
However, since the noise only occurs when the engine has been shutoff for several hours, it does seem to be related to a system that slowly depressurizes (which is why I suspected a fuel pump). But that's probably in the tank (in the back), I'm guessing.
Tuesday, June 8th, 2010 AT 3:54 PM