Hourly "Stop Engine" and "Check Engine" Lights on 6TS Cat

Yesterday the Western Star started giving the Stop Engine and Check Engine warnings on the dash.

We think this engine is on its way out, because a few weeks ago it started occasionally puking water out the radiator overflow and making pressure in the coolant reservoir. So when it would puke out water, the low coolant sensor would give it the warnings. With it cool, we'd shut it down, add coolant to the tank, and when we restarted it it was fine. The past couple of weeks it hasn't had a problem.

Last weekend it sprung a coolant leak from a worn hose. Fixed it and refilled. Noted a worn spot on the wiring harness at the front of the motor. But ever since, about once an hour, he's getting both warnings.

This morning he unplugged the low coolant warning sensor to see if it was the sensor. When he restarted it the warnings were gone, but SURPRISE, still had the warnings come in right at an hour later.

So, what the (heck)? What would cause the warnings to come on in an hour? Or just bad luck? He's been keeping the coolant reservoir topped up to the inside of the filler neck just to be sure.

Any input from Cat experts would be appreciated.

 

Okay. That makes sense. It just seemed screwy that it would come on after an hour.

Thanks