I have 2 salespeeps and 2 mechanics tell me that a thermo clutch fan should be fully engaged on cold to warm, while slippy on hot. and the amount silicon oil should be full... they say silicon oil will become slippy when it is hot enough...

contrary from what I learned from the net. that thermo clutch fan should be parialy engaged on cold-warm and becomes fully engaged only when reaching a particular hot temperature.

then if the silicon oil is full, it will make the fan always fully engaged. and I think silicon oil does NOT become slippy when hot, but it's the mechanical thermostat thingy that pulls the silicon oil on the inner part making it engaged when hot enough...

need your input guys, which is true? and how much silicon oil do I really need?