My car has developed a strange whistle/rattle sound that starts when the rpms are above 5000. I've had header leaks at the head that sounded simular so I checked the bolts out, and they were tight. While under the hood I noticed the fluid damper had white streaks on the face, I tried to wipe the substance off but it seemed to have dried to a hard finish. Does this mean my Fluid Damper is toast? Anyone ever had one go bad?

 

It should have a lifetime warrenty. Try e-mailing the manufacturer and asking them.

 

One other thing you might want to check that can cause a whistling sound is your smog pump. The air pipe that comes out of the back of the pump has two bolts that hold it on. My car was making a strange whistling noise, and it turned out that those two bolts holding the pipe on the pump had worked their way loose. Not sure if this would cause a rattling noise as well, but it couldn't hurt to check it out while you're under the hood. And yeah, if your fluidamper really has gone bad, they should replace it free of charge under the warranty.