GlenQ
Active Member
This is a short how-to on replacing a noisy (failed bearing) radiator fan motor on a year 2000 W220 S500.
Now your stealership will tell you that if your radiator fan motor is noisy you will have to replace the whole assembly including cowl , fan, motor and drive belt at considerable cost.
This is not necessary as the motor alone can be replaced.
First purchase your new motor. I got mine from a trader here. It also came with a new drive belt. *****Please see caveat below*****
New motor:
Disconnect the electrical connection to the motor then remove the plastic motor cover by prising open the two push pin type fixings this will expose the motor.
Next, remove the two bolts that secure the top of the cowling to the frame of the car ( I took the photograph before I pulled of the air intake hose so remove both hoses before removing the cowling bolts)
Now remove the lower two bolts that secure the motor to the cowling leaving the third one loose but still in place.
Now raise the whole cowling assembly upwards (the bottom of the cowling is not bolted, instead it has two pegs that locate in holes in the cars frame). The cowling will be able to be lifted a couple of inches from it's original position but will not be able to be removed altogether because of various rubber hoses. Now that the cowling is lifted up it can now be pushed backwards at the top towards the engine just enough to allow access for your hand to be able to pass between the radiator and the cowling so you can remove the drive belt which will be easy now that the motor has been loosened in the cowling.
Once the belt has been removed settle the cowling back in it's position and remove the remaining loose mounting bolt and remove the motor from the cowling.
Fitting the new motor is quite simple. First fit the new motor to the cowl using the three bolts (tighten all three bolts) then lift the cowling up and back to reveal the motor and fan pulley's again and run the belt around the motor pulley and start it on the fan pulley. Now if you rotate the fan the belt will be pulled on to the fan pulley (this bit is fiddly but the belt will pop over the pulley after a few tries). This part of the job is made harder because there is only a small gap to work in between the radiator and fan cowling.
Once the belt is around both pulley's the cowling can be dropped into it's lower mounts and bolted up at the top. Re-connect the electrical connection and replace the motor cover and test. You should now have a silent cooling system again.
Important:
Before bolting up the new motor make sure that the motor fits OK in the cowling in it's final position and that ALL of the three bolts are aligned with the mounting position.
During the installation of my new motor I discovered that the motor brackets did not align exactly with the mounting position in the cowling so I has difficulty in lining up the fixing bolts. As I was tightening the bolts I heard a sharp crack and discovered that a third of the plastic motor pulley has sheared off.
There is a very small tolerance between the pulley and the cowling. This misalignment of the motor mounting bracket / holes in my case was what caused the pulley to break when I tightened up the bolts so be carefull that your motor lines up perfectly with the cowling and make sure the pulley does not foul the cowling before the final tighten-up of the bolts.
Apart from the above and the cramped conditions between the cowling and the radiator during belt installation this is a simple job that should save a bunch of cash if your motor fails or gets noisy.
Now your stealership will tell you that if your radiator fan motor is noisy you will have to replace the whole assembly including cowl , fan, motor and drive belt at considerable cost.
This is not necessary as the motor alone can be replaced.
First purchase your new motor. I got mine from a trader here. It also came with a new drive belt. *****Please see caveat below*****
New motor:
Disconnect the electrical connection to the motor then remove the plastic motor cover by prising open the two push pin type fixings this will expose the motor.
Next, remove the two bolts that secure the top of the cowling to the frame of the car ( I took the photograph before I pulled of the air intake hose so remove both hoses before removing the cowling bolts)
Now remove the lower two bolts that secure the motor to the cowling leaving the third one loose but still in place.
Now raise the whole cowling assembly upwards (the bottom of the cowling is not bolted, instead it has two pegs that locate in holes in the cars frame). The cowling will be able to be lifted a couple of inches from it's original position but will not be able to be removed altogether because of various rubber hoses. Now that the cowling is lifted up it can now be pushed backwards at the top towards the engine just enough to allow access for your hand to be able to pass between the radiator and the cowling so you can remove the drive belt which will be easy now that the motor has been loosened in the cowling.
Once the belt has been removed settle the cowling back in it's position and remove the remaining loose mounting bolt and remove the motor from the cowling.
Fitting the new motor is quite simple. First fit the new motor to the cowl using the three bolts (tighten all three bolts) then lift the cowling up and back to reveal the motor and fan pulley's again and run the belt around the motor pulley and start it on the fan pulley. Now if you rotate the fan the belt will be pulled on to the fan pulley (this bit is fiddly but the belt will pop over the pulley after a few tries). This part of the job is made harder because there is only a small gap to work in between the radiator and fan cowling.
Once the belt is around both pulley's the cowling can be dropped into it's lower mounts and bolted up at the top. Re-connect the electrical connection and replace the motor cover and test. You should now have a silent cooling system again.
Important:
Before bolting up the new motor make sure that the motor fits OK in the cowling in it's final position and that ALL of the three bolts are aligned with the mounting position.
During the installation of my new motor I discovered that the motor brackets did not align exactly with the mounting position in the cowling so I has difficulty in lining up the fixing bolts. As I was tightening the bolts I heard a sharp crack and discovered that a third of the plastic motor pulley has sheared off.
There is a very small tolerance between the pulley and the cowling. This misalignment of the motor mounting bracket / holes in my case was what caused the pulley to break when I tightened up the bolts so be carefull that your motor lines up perfectly with the cowling and make sure the pulley does not foul the cowling before the final tighten-up of the bolts.
Apart from the above and the cramped conditions between the cowling and the radiator during belt installation this is a simple job that should save a bunch of cash if your motor fails or gets noisy.
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