I switched from the original engine cooling fan which did not work very well a to a flex fan which runs whenever the engine is running. The fan blades flex and thus push less air as engine speed increases. Does a fantastic (pun intended) job cooling the engine. BUT..... the fan makes so much noise you can forget conversation at highway speeds. I tried several different spacers and did get the noise below jet turbine level. Have any of you gone to an electric fan with no engine driven fan? If so are you satisifyed with the result?