Hey, I've got a '95 ranger 4 banger, and am hearing a strange whining noise while driving. It starts out really soft and quiet but gets progressively louder and louder. only seems to happen at highway speeds (50+mph). The whining/humming sound seems to stop when I either take my foot off the gas, slow down some or throw in the clutch (5spd. manual).
Any ideas out there? I used to add a little power steering fluid and the sound seemed to go away. now that doesn't seem to work and I'm not convinced that it is the power steering pump.

 

do you have a supercharger lol jk...could be a wheel bearing or an engine pulley...but im kinda thinking a bearing

 

my 89 sounded supercharged but it was just the powersteering pump

 

no, no turbo. that's an idea, though. but when I increase speed the sound dies down rather that getting louder, so I think it's not a wheel bearing.

 

Ok, so I think I know what happened to it. I had a mechanica take a test ride with me and he thinks it's the heater core of all things. Apparently ford shaped it funny so when the fluid/air goes across it at a certain speed it makes a strange sound. I'm not positive this is the problem, but it's the best I've got so far.