BLUE TEMP SENSOR,

[arrisbmw]

I just check my blue temp sensor ( thermistor ) a resistor that varies its resistance value according to temperature changes.
At the ecu plug you need to put a multi meter on ohms across pin 24 grd and 45 ( see e30 wiki ) motronic engine managemnet 1.1 and 1.3 (55 pin connector) the reading i got at cold well today 2633 ohm and checked again following a short run = hot 198 ohm
does that sound about right. ?

I believe my viscous fan is not working properly , as i could stop it with warm engine ( rolled up news paper test ) it didn,t seem to have any more resistance with cold or hot engine ??? any one more experienced any comments please.

thanks

[Brianmoooore]

Readings are reasonable, although the hot reading is a little low. Maybe that's because your viscous coupling is dead, and the reading was taken at a higher temperature than normal.
Not a fan of the so called 'rolled up newspaper test'. Easiest way to test the coupling is to hold the engine at
a fast idle with the heater off, and watch the temperature gauge. The temperature gauge should gradually rise slightly, and then stabilise well away from the red sector. If the accelerator is pressed at this time, there should be a loud roar from the fan.
If instead, the temperature doesn't stabilise, and continues to climb until it's approaching the red, then the coupling has failed or the radiator is well past its best.

[arrisbmw]

thanks , the rad is new, and temp sits steady at near half way. but i did notice on a fast motorway run if i give it the beans , it goes just above half way and when i put the heater on full it came down to near half way . m4016b , does the fan suck or blow. ?

[Brianmoooore]

Fan does nothing when moving over 20 MPH. It's only there for sitting in traffic or stationary.
It sucks through the radiator.

[arrisbmw]

thats interersting . thanks again.