Originally posted by acschnitzer@May 23 2006, 02:33 AM
Sorry if i am mistaken but isn't the fan running at all times as long as the car is running? Thought the only fan that will go on/off is the aircon fan that depends alot on the thermostat. The main fan still runs as long as your car engine is on. Should the car starts to overheat even when the aircon's off, from my experience, it's actually time to change the fan cltch to keep it up to speed so the car doesn't overheat. Do share your opinions.
The clutch fan is engaged through fluid dynamics. The clutch fan contains a viscous liquid which, when hot, expands and pushes against the bi-metal bracket (the metal piece that is fitted at the centre of the fan clutch, thereby engaging the fan. As the engine cools, the fluid shrinks back and the clutch disengages.
I find that it works extremely well on my e21 and is fairly reliable, it will not die suddenly on you. Electric fans either work or don't work - can die on you without warning.
The aircondition fan does very little to keep the engine temperature down. Again, on my e21, my ac fan is getting weaker, not pushing enough air.... temperature goes pretty high with ac on when stuck in traffic. AC off - temperature is steady under the same conditions (only thing is, I end up drenched in sweat).
As with all mechanical items, there is a limit to how long it lasts. Better to change earlier, rather than later. Otherwise "penny wise, pound foolish" might apply.
Have it inspected by your regular mechanic and let him give you the proper advice.
