Cooling fan info for the Maliwagon

[Rt Jam]

Get an adjustable controller so you can set the OFF temperature. It must be set higher than the thermostat temperature. This ensures you NEVER have the scenario where the fan is running on a closed radiator. This also allows the thermostat to regulate the temperature on the highway and the fan doesn't run at that time or speed.

I don't like controllers with the probe in the radiator fins. Had that set up before. Maybe it was just my car but when cruising slow there was not enough air flow through the radiator, so the engine starts to get hot but the controller does not recognize this since wind is cooling the probe. Sensor into coolant only.

The better set up is with PWM fans but that is a whole other thread.

 

[Sweet_Johnny]

Fans: NMB- Standard Duty, NMC- Heavy Duty, NMS- Severe Duty

When it comes to electric fans I like to set the Low setting to come on 10° above the thermostat rating and avoid the situation of useless fan operation that Rt Jam references. I also agree with their feelings on temperature probes.

Since water boils at 210° we like to run the engine that hot 50% of the time to clean it, but you never really want to get above 240° for a "play" car. For this, simply treat it as if the AC were on all the time- it is under load after all. For reference, '97-'04 Corvette Low fan speed is 226° and high speed comes in at 235°, but at only 185° if the AC is on and driving under 40 mph.

BMW sensor/switches thread into the coolant passage just like our usual pieces, have 2 temp settings, and can activate both the Low and High speed settings. If you have twin dual-speed fans you can sometimes use 2 switches. Not all 2 fan setups can be spit into dual 2 speed setups since many simply split the 12 volts between the 2 to activate Low speed, and go full voltage for High. You may have the option of turning on Low then High for one fan then repeating the process, or you can do Low, Low, High, High. Or just stick with both fans operating at Low/High together. One fan on High is often louder than two on Low.

But if you can operate each fan individually then BMW 61311378073 activates at 195° and 210°, and 61318361787 does so at 175° and 190°.

There are other switches available too, like the ones from t7design.co.uk. The 1DF-53C-336 turns on Low @ 200 off @ 190, High @ 207 off @ 198. I lost the part # for the better ones that turn on @ 207 & 214 and off @ 198 & 205... But my pick to pair with a 180° thermostat is part # 06B-C34-24C which turns on @ 195/ & 200 and off @ 180 & 190, and CD8-C93-66C which turns on @ 207 & 215 and off @ 198 & 205. With these two switches you can dictate 4 different activation and termination temps to basically micromanage your operating temp., all without needing a computer of any kind.