2015 mx13 paccar ?

On a cold start level drops and it beeps but if I add fluid it spits it out.. mine beeps for maybe 3 or 4 minutes .. it’s been like that since new if I add antifreeze I need to add daily however if I don’t it stays at the same level forever .. kw said I had 500 plus low antifreeze warning in ecm history .. I was told let it beep the 3 or 4 minutes and not worry unless it did it warm

 

Plastic coolant reservoirs have a fluid level sensor on the bottom that just slips into a straw type opening that's held in place with 4 plastic tabs of the reservoir. Just replaced a sensor last week that had 4 nubs on the sensor that correlates to the locking tabs of the reservoir. The nubs had worn way down and allowed the sensor to vibrate down out of the res just enough to give a low warning without actually being low, no problem with the sensor, just wasn't in the correct position.

 

I have a 2019 T680 with the same problem. I hacked a solution to the problem with a magnet and 2022 version of baling wire. All alarm lights and sounds are off and truck runs fine. Just do your precheck and eyeball the antifreeze reservoir, keep an eye on your engine temperature gauge and use your nose to sniff out any antifreeze odor. You don't need no stinking low coolant sensor. Pics are attached.

 

I don't think its common. I have never had any issues with mine. Sensor must be off. Make sure you are on level ground that fluid level may be off when you crank it up cold and it's on a slope. Calling out a false positive.