I have '99 v6 mustang. Recently I started hearing a screeching noise when it got up to about 4,000rpm. At first I thought it was the belt or a bearing on a pully. I changed the tensioner and idler pullies, but that didn't fix it. I took the belt completely off, started it up and at 4,000 rpm it still made the noise. Sounds like its coming from the top of the motor. Does anyone have an idea of what this is? Could it be a camshaft bearing?
-Zach