Fan Speed

[NWIP]

I have been using (more like playing) with different parameters shown by BlueFire and recently added fan speed.

Now a couple of questions for those that have monitored fan thru VMSPC, BlueFire or those that have knowledge of fan operation. Fan seemed either on or off as shown by either 0% or 100%, is it a variable fan? What makes the fan operate? Below is what I saw recently which made me think I don’t know how this should work, side radiator on Freightliner.

I have never seen my normal temp guage much above the 1/4 mark under different conditions, outside air temp or road conditions. Yesterday was the first time I saw it reach the 1/2 way mark on trip from Las Cruces to Tucson; outside temp approximately 65 and steady climb on various portion of the trip. What I noticed is even though driving conditions didn’t change once the temp reached 1/2 way mark fan speed changed from 0% to 100% and the temp would reduce back to slightly above 1/4.

Please educate me on what is normal operation of fan! Thanks

[ptw]

Do you ever monitor the coolant temperature from the digital readout on the message display center on the dash?

Normal driving on flat land I find my temperature stays very constant around 180 degrees. There were a few times I noticed the temperature going over 190 for no apparent reason. Over time I realized that when the air conditioning is on the fan runs on high speed so the engine temperature remains a more constant temperature. When the AC is off the engine temp varies more, especially in start/stop driving and hills.

Driving in the mountains with the air conditioning off the temperature will start to rise, the fan will switch to high and you will see the temp come down.(I don't remember the temp high speed kicks in, around 210?)

Here is some info on the fan drive

"VS Variable-Speed, Directly-Controlled Fan Drives
VS Variable-Speed, Directly-Controlled Fan Drives are managed by the engine’s electronic control unit (ECU) to provide precision fan control, increased cooling performance, improved fuel economy and less noise. Designed for a wide range of applications, they are offered in several sizes and three control configurations, including on/off, PWM (pulse- width-modulation), open loop and PWM with integrated speed monitoring control.
• Rapid response time (fan speed engages in 10 seconds and disengages in 10 to 30 seconds depending on engine speed)
• Compact size with greater torque for lightweight, powerful performance
• Double-row bearings for durability and longer product life
• Rear electrical connection harness to shield electrical connection from the fan blades"

[NWIP]

Originally Posted by ptw

Do you ever monitor the coolant temperature from the digital readout on the message display center on the dash?

Normal driving on flat land I find my temperature stays very constant around 180 degrees. There were a few times I noticed the temperature going over 190 for no apparent reason. Over time I realized that when the air conditioning is on the fan runs on high speed so the engine temperature remains a more constant temperature. When the AC is off the engine temp varies more, especially in start/stop driving and hills.

Driving in the mountains with the air conditioning off the temperature will start to rise, the fan will switch to high and you will see the temp come down.(I don't remember the temp high speed kicks in, around 210?)

Here is some info on the fan drive

"VS Variable-Speed, Directly-Controlled Fan Drives
VS Variable-Speed, Directly-Controlled Fan Drives are managed by the engine’s electronic control unit (ECU) to provide precision fan control, increased cooling performance, improved fuel economy and less noise. Designed for a wide range of applications, they are offered in several sizes and three control configurations, including on/off, PWM (pulse- width-modulation), open loop and PWM with integrated speed monitoring control.
• Rapid response time (fan speed engages in 10 seconds and disengages in 10 to 30 seconds depending on engine speed)
• Compact size with greater torque for lightweight, powerful performance
• Double-row bearings for durability and longer product life
• Rear electrical connection harness to shield electrical connection from the fan blades"

Paul

Thanks for your input, I have drove with AC on for the majority of the 18,000 miles we have put on the coach and stable temp of 180-190 is what I have seen. This last leg of trip no AC running and fan was coming on when temp reached 210, which you confirmed.

I felt everything was normal just was surprised that fan only seemed to be running once temp got to 210 and would shut off completely once temp came down. This was during highway driving and too busy to watching traffic while I’m town.

Thanks