95 Ford Explorer makes a low pitch howling noise from engine

Hello, Our Ford Explorer at times makes a low pitch howling noise from the engine. The noise occurs usually in the summer months, always after I have driven any distance of more than 5 miles. The noise will sometimes occur after the engine has been stopped and restarted. As I accelerate the noise will sometimes go away. The harder I accelerate the quieter the noise gets. So it seems to have something to do with the air intake tunnel. Any suggestions, other than not to drive in the summer!!!

Thanks in advance.

Tim

If you think it’s comming from the air intake…change the air filter and see if that helps. However, the noise I hear in my Explorer is the fan. As you accelerate the noise goes away because the fan clutch disengages and this noise is normal.