Fan blade replacement issue

I recently repleced the water pump, water pump pulley, and fan blade on my z3. i decided to do this myself and it wasnt too difficult but the fan blade is alot louder than the OEM one i had on before. is this normal or could it have to do with the fan blade itself??

possibly on backwards?

no that ws one of the first things i looked at. but its on the correct way. im actually working on it right now to see if maybe i put on the fan blade t the fan coupling wrong, but it looks fine. perhaps its just the fan blade itself. cheap plastic.

It sounds like a faulty fan clutch. These fans are LOUD when the clutch locks. The clutch should freewheel when cold, and stay "open" until the engine reaches high-normal operating temperatures. In your case, your fan clutch might be engaged permanently or engaging prematurely. When the fan clutch is operating properly, it is possible (with great care!) to stop the fan with the engine idling at cool to normal operating temps, but it is not something I would recommend doing if there is a chance it won't stop easily...

-Kyle

so the fan clutch is the fan coupling, correct? cause i dont think it was damaged when the water pump broke. i replaced the water pump, along with the pulley and fan blade. any recomendations on what i can do with the fan clutch?

Originally Posted by BMW_Z3

so the fan clutch is the fan coupling, correct? cause i dont think it was damaged when the water pump broke. i replaced the water pump, along with the pulley and fan blade. any recomendations on what i can do with the fan clutch?

Best thing to do when you are there is replace as much as you can afford.

So it looks like it is the fan clutch. The strip that appearently reads the tempature was off the clutch. i tried putting the strip back on but still doesnt work. i was looking up some fan clutches and it looks like there is thermal and non- thermal. would either be fine on my z3?

Originally Posted by BMW_Z3

...it looks like there is thermal and non- thermal....

I had no idea non-thermal viscous fan couplings were in existence. What is the difference?

'Non-thermal fan clutches operate based on the water pump shaft speed. When the water pump shaft is spinning at low and idle speeds, the clutch will spin the fan at about a 1:1 ratio. During high speed rotation the silicone fluid within the fan clutch reduces its ability to spin the fan at full speed and the energy transferred from the water pump shaft, through the clutch to the fan is reduced. The result is less load on the engine as the fan almost free-wheels'. I dont even think they make non thermal clutch fans for the Z3 but they dont seem to have an advantage on the thermal clutch fans anyway.