Originally Posted by Dr. Flyview
The way I understood it, the actual engine fan doesen't change speeds. It's always spinning at a medium rate. That's why there's a mechanical clutch which doesn't allow it to spin up to the engine's revs (too tight), but also doesn't let it stop spinning (too loose).
There is ANOTHER electrical engine fan (auxiliary fan). This one has 3 speeds: off, low, and high. If you have a mechanical clutch fan (above), you should really only hear this come on at idle when there's little airflow into the rad. It is controlled by a temperature switch that goes into the radiator. Perhaps if this is the aftermarket one you're talking about, it's no longer connected to this switch, or doesn't correctly interpret the readings.
BTW you don't want a fan to be too fast or on when it's not supposed to be, since you may run the engine too cold.
I think the manuals came with an electrical fan while the auto/step trannies came with the clutch fan (which is what I have).
Also, surprisingly, I don't think the engine takes any longer to warm up.
BTW, when the hood is open, I can hear and feel the fan on (blowing air). Revving the engine causes the fan to go faster too (increasing noise).
BTW Eurostyle, I will give you a call tomorrow, got busy today (I called you in the afternoon but wasn't able to after that).