waterpump and fan?

[eclipsevrl]

How does a bad waterpump cause the radiator fan blades to break off?
97 328iC Automatic 115K

2 months ago I got my waterpump replaced. Next thing I know is that my fan blades broke off. Then I got a new fan and fan clutch.

Last week fan broke again... Took it to a BMW speacialist. They said the engine mounts looked fine.

They changed the waterpump, fan, shroud, radiator. Note all oem parts.

The old waterpump (2 months old) the metal impeller does not spin around freely, it seems as it broke. Note it was an aftermarket part.

My question is... can a bad waterpump cause the fan blades to shear off???

Can this bad waterpump be taken back to the parts store, i've got all my receipts... and will they be responsible for the fan...etc?

Thanks for your input.

[DesmoBob]

so it looks like the common denominator with the two fan detonations is that 2-month old water pump. or at least the installation event. if your water pump bearing failed it may have introduced a wobble. or it could have been bad installation technique (like not properly re-clipping the radiator).

although it's not necessary to touch the radiator, when they changed the pump (2 months ago), did they remove or in any way manipulate the radiator for pump access? even if the fan or anthing sharing the drivebelt has no wobble, the radiator could have been loose (held on only with clips). the fan does suck the radiator toward it.

i doubt the parts store will claim any responsibility for anything other than the failed water pump. they may say you can't prove the water pump caused the fan to grenade.

how is it running with the new (week old) water pump?

[97alpineM3]

Yes the water pump drive shaft which is directly attached to the extension that turns the fan is related to the blade breakage... if the shaft it self within the water pump fails... that causes the fan to move in odd directions... thus hitting other things like the shroud... and radiator...

Les

[bitcore]

I found that the engien fan is REMARKABLY CLOSE to the vanos solenoid that sticks out from the engine. I've gone through this escapade a few times requing me to remove the fan clutch and replace the fan myself from one I got from autohausaz.com (cheep OEM!)

My water pump bearings failed, the tension of the belt made the shaft cockeyed at about a 30 degree angle from normal. Tore up all kinds of stuff and left me stranded in raleigh with my.... now ex... lover (that was an amazing 5 days & will miss them forever.). They replaced pump, fan, shroud, pulley and belts. A week later the fan broke again. Replaced it myself and havn't had a problem since.

http://alt.bitcore.org/stuff/water_pump.jpg