Temp sensor for 2 stage fan E21 323i

[Atle_323i]

I wonder if there is another temp sensor with lower temperatures than original 91 og 99 degree for the 2 stage fan speed control.
I think 91 and 99 degree is abit high, because the temp rises over mid on scale on my car, before the fan starts to run. I don´t want the engine to run too hot.
The fan should start to run at lower setpoint, to prevent engine "overheating".

Does anyone know if there are other sensors with lower degree that can be used?
Like 88 and 95?

[Jeroen]

iirc the 1st stage (slow speed) should start just after the needle passed the halfway mark, and in most cases this should be sufficient. As a failsafe and on really hot days, the 2nd stage (high speed) starts around the 3/4 mark.

If your temperature is quite high all the time and you are sure the components of your cooling system ar ok (especially radiator, coolant tank cap and fuel pump) you may want to consider a different thermostat. Stock is 80 degrees, I switched to 71 degrees. Coolant temp gauge is just above 1/4 when cruising (72 degrees), just below halfway when stepping on it. Oil temperature is hardly affected (max 2 degrees lower) so no lubrication issues.

Thermostat is Behr/Hella TX-27-71D

[Atle_323i]

iirc the 1st stage (slow speed) should start just after the needle passed the halfway mark, and in most cases this should be sufficient. As a failsafe and on really hot days, the 2nd stage (high speed) starts around the 3/4 mark.

If your temperature is quite high all the time and you are sure the components of your cooling system ar ok (especially radiator, coolant tank cap and fuel pump) you may want to consider a different thermostat. Stock is 80 degrees, I switched to 71 degrees. Coolant temp gauge is just above 1/4 when cruising (72 degrees), just below halfway when stepping on it. Oil temperature is hardly affected (max 2 degrees lower) so no lubrication issues.

Thermostat is Behr/Hella TX-27-71D

The fan stage one starts just over half, which is how it is supposed to be. There could be poor cooling from the radiator. It had alot of rust water, when I took it out of the donor car. I flushed it, but there still are brown stuff at the inlet and outlet. So the radiator could be in bad condition, and the rust can block the the cooling efficiency.
A new radiator cost about 700 euro, so It´s not cheap. I have an 71 degree Behr thermostat which I want to try and use, before buying a new radiator.

Worst case is that I can just make an override button in the dash, to activate full fan speed, to keep it cool when the car is running in traffic. That is when I have issues.
As I have an 80 degree thermostat with a 5mm whole to let some cooling pass through the radiator. This makes the car run between 1/4 and 1/2 on the temp gauge.

[Jeroen]

Manual override defo is a good option as well, as soon as you run into traffic you can start cooling instead of waiting for the temp to rise

[uwbuurman]

Mine is a type 1, hence electric fan. Also two temp switches and like Jeroen I fitted a different one than stock. The lower tempnis now a 87°c 82°c. And I made a manuel override for the high temp switch. That is for hot engine, sudden stops like traffic lights of bridges.

[Atle_323i]

Mine is a type 1, hence electric fan. Also two temp switches and like Jeroen I fitted a different one than stock. The lower tempnis now a 87°c 82°c. And I made a manuel override for the high temp switch. That is for hot engine, sudden stops like traffic lights of bridges.

I guess a switch to override the fan is the easiest way to go, as I just need to short the high temp switch to make the fan go at full speed.

[uwbuurman]

Yeah, thats what I did. Hooked it on to the front foglight switch, since I don't have front foglights.