W123 overheating

[stever]

Hi All

I have a little problem with my 1984 230E I hope someone may be able to help with:

when sitting in traffic for a long time, the engine starts to overheat. It appears that the electro-magnetic fan is no longer kicking in as it should (it used to kick in at 100 degrees). From old threads on here, it seems that the temp sensor is the likely culprit and I can test it by shorting it out. There are two sensors next to each other at the front of the engine - one has 1 pin, the other has 2 pins. Old threads on here suggest it's the 2 pin sensor, yet Eurocarparts list the replacement sensor as 1 pin. Does anyone know which one it is?

Thanks.

 

[stever]

Not one reply!

To answer my own question - I have traced it to the single pin sensor. W123 230e owners should note that the advice given on here in the past for W124s and 201s is incorrect for their car.

 

[grober]

Better late than never!

Sorry I didn't spot this earlier STEVER. Whatever the configuration of the switch the principle is the fan clutch is powered/live 12v via the ignition switch all the time and only activated by earthing it via the switch. Good to know the w123 uses a single pin switch to achieve this- I assume the body of the switch acts as the earth connection. Later 201 models do in fact use a 2 pin switch and in the case of models with A/C a a 3pin switch!

 

[stever]

Hi Grober. That makes sense - I got the fan to activate by earthing the single-pin switch plug to the cylinder head. The switch only costs about £12 so a cheap fix...