,,,,And completely normal for it to disengage when not needed, which is pretty much all the time if you are moving at a decent speed and/or not towing. (After it originally disengages, I have yet to have mine come full-on, even in Houston stop and go traffic @ 100+ degrees.)
The only 'drag' a viscous clutch places on your engine while disengaged is from the 2 ball bearings inside the clutch while the fan free-wheels.
And even that miniscule amount of bearing drag is not a complete waste. It does (with complete silence) pull just a small bit of air over the rad.
Viscous clutches are probably one of the least understood parts on a modern engine. So many folks know so little about how a viscous clutch works. The unknowing think if you take a viscous clutch that's been sitting for a while (engaged) and spin it by hand, that it ALWAYS has that much drag. Nope. Clutch has to be spun several hundred times (in the right direction) to allow the fluid to pump out of the finned grooves before it disengages.
Still confused? Go here:
https://www.youtube.com/watch?v=N_GkuTgJr3w
I wonder how many electric fans have been sold by folks twisting a viscous clutch after it's been sitting a while??? Wouldn't surprise me that unscrupulous sales folks would have one laying on the counter next to the 'lectric fan display,,, "Here, twist this,,, see how it's robbing your HP?"
LOL!
