[viking427]

If you go with an oem viscous coupled ("clutched") mechanical fan, get the matching shroud also. The fan blade tips should protrude 1/2 in and 1/2 out of the shroud. I agree the better electric fans are more efficient, but I've never had a set last more than a few years without some sort of problems (seizing up, relays, controllers etc.). where my oem clutched mechanical fans seem to last decades trouble free.