Hello,
I was hoping to get some help with this one. I just bought a 2001 V70 auto wagon with 70K miles, no turbo, no AWD. There is a vibration that can be heard only at 2000rpm's, but not felt through any of the pedals or the steering wheel. When I have the window down and have the car accelerating through 2000rpm's I can also hear a slight rattle like nails in a coffee can that accompanies the vibration; the rattle starts and stops with this vibration. The sounds are louder when the car is under load accelerating; I can also hold it steady at 2000 and keep the vibration occuring continuously (it is not as loud as under acceleration), but the rattle is barley evident. As soon as I go above or below 2000 by only 100rpm's or so, there is immediately no more noise, whether accelerating or holding steady. I can slowly rev the motor up to and through 2000 in Park and have no rattling or vibration at all, doing the same thing in Neutral both when moving or not moving produces a very slight vibration noise, but no rattling. The motor is slightly rough for about a second on startup and shutdown. I also have what is probably a bad brake booster that hisses as others have described.

I have already read on this forum that I should check: plugs- spark and gaps, plug wires, injector sprays, the motor mounts and ignition coils. I will look at all of these things. I was wondering though, if none of the other parts mentioned turn out to be the reason, if there was an exhaust heat shield or another part that is known to come loose and could be resonating when the motor hits 2000?

Any input would be greatly appreciated.

Thanks,
Paul

 

Could be a problem developing in the front bearings? I had the same problem which got louder over a six month period until it was unmistakenly the left bearing! Good luck!

 

Catylitic converter shields will often vibrate and make a horrible noise . The noise you describe is exactly what I had in my old car. It was the housing for the converter rattling. Check it out while you are doing your inspection.

 

Thanks to both of you. I will look into both of those. Does anyonse else have ideas as well?

 

My Vote is for the Cat itself.
Try hitting it with a rubber mallet or your Hand(When cold) and see if you hear the Rattle.

 

Thanks tech, I see you are one of the resident experts on this forum. I was hoping you would also give some input. I appreciate that, I will let you all know what it turns out to be.