C209 Radiator Fan

[Harchy]

My 2008/09 CLK 2.1CDi (150HP) has developed a lazy radiator fan. It doesn't always operate when the engine is ticking over such as when stuck in traffic, causing coolant temperature to rise.
It gives a dashboard message but no warning light, showing a thermometer and some wiggly water!
Have tried to obtain replacement fan but apparently no longer available from MB. Same reply from after-market mfrs. Part no. is A2035001793
Any suggestions.

 

[slade1]

Google the part number

 

[Harchy]

Yes, tried that. That is how I discovered there are no replacement fans/blowers from MB or the aftermarket mfrs.

 

[Harchy]

Some aftermarket mfrs list a suitable replacement as A2035001693.
Reply from MB Portsmouth:
That part No A2035001693, doesn’t come up as applicable for your car on our system.
I can see that it’s listed but is not interchangeable with your one A2035001793.

 

[Trickythemerc]

Are you sure the fan is faulty ? Other things to check are the thermostat, just changed mine @ 124 K pretty certain a sticky fan relay could also be at fault.

 

[Harchy]

Are you sure the fan is faulty ? Other things to check are the thermostat, just changed mine @ 124 K pretty certain a sticky fan relay could also be at fault.

Thanks. I'll check. Replaced the thermostat at about 80k.
Now done 120k and still goes like **** off a shovel!
Also discovered new problem - heating not working. Heater fan kicks in if I turn up the temperature, but no hot air.
Does the same whether air-con is on, off or on auto.
Recently had new water pump fitted. Could there be an air-lock? Coolant temp is usually at 85deg.

 

[Harchy]

OK, so checked wiring diagram and there isn't a relay for the fan.
Positive to fan has a fuse, an earth of course, a connection to the ECU which communicates to fan motor, and a connection to ignition.
Any other suggestions?

 

[IanW]

My W209/CLK500 developed a similar fault a couple of years ago. Star in Reading diagnosed a faulty fan control module. It was replaced with a new unit & has been fine ever since. The fan motor itself has never had a problem.
The part number you quote looks to be the motor and shroud, not the electronic module. Can you communicate with the fan controller using a diagnostic tool? IIRC, both the engine and HVAC sections of the M-B specific diagnostic tools report the requested fan speed (as a percentage) and the actual. Faulty comms or stupid fan speed numbers would suggect faulty electronics rather than the fan itself.
I'm afraid I don't have the module part number.
Ian.

 

[Harchy]

Thanks Ian. I'll check with my garage.