Hello,

I recently got back my 2001 Impreza RS from with a 2.0 WRX motor swap in it. The transmission remains unchaged outside of an upgraded clutch. The car has been running great the past few days, but it's been making a noise since I got it back. Here is the issue:

At 70-80mph the noise begins, it's a low humming noise. It doesn't really get louder with higher speeds, and it happens regardless of the motor. The noise is still there in neutral or clutched in. I am not sure whether to chalk it up to a bushing or something new vibrating with it because it is a brand new motor in a car with 80,000 miles on it.

I've read other threads and I've heard people suggest diffs or wheel bearings, but it seems odd it went bad after the swap but made no noise before it was done. I also though it might be the front bumper or fenders vibrating, but it seems weird it does it only really begins at 70+ and is perfectly quiet before that speed.

Thanks :)

I have had a similar problem with my 00 RS. It does it at 70+ MPH. I adjusted the rubber stoppers on the rad support for the hood and the noise went away. yo might want to check that.

Thank you, I'll take a look at it tonight and see if that's the problem :) I tried pushing my broken splash guard out of the way, but that only solved the problem of the splash guard rubbing against the tire at low speed when making a U-turn.