Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Use a class 2 scan tool to see the actual engine temperature when the gage spike is present to verify gage accuracy.
With engine warmed up & heater on,go under hood & feel both heater hoses.Are the both hot & close in temperature ? If not you have an obstruction in the heater core.If they are hot you most likely have a failed temperature actuator.There is usually a code set in the Body Control Module for this condition.