I recently bout a 1994 Chevrolet 3500 6.5L diesel. For some reason my “low coolant” light will come on. And my temp gauge stays about a 1/4 way. An will rise at times to full hot but with in two seconds it will go back down to 1/4 way. Heat blows great. My second issue is I am having white smoke coming out of my dipstick while the engine is running. It will only blow white smoke at startup from the exhaust then nothing. Runs great. Has 114k miles on it. I’m not big on diesel motors but can definitely fix anything with some directions or tips.