Question I changed the anti freeze 3 months ago (dexcool), new cap,and new thermostat .. when completed, temp.goes up and down while driving and more heat while driving (very little at idle) some say an air bubble is in the system ... can this be true?? 1995 Chevy Tahoe
AnswerYes, an air bubble can get trapped in the cooling system.
Try to find a steep hill, park the vehicle nose up, and leave it until it cools completely down (or overnite).
Before starting it again, remove the radiator cap and see if you need to add coolant. I think that you will find that you need at least a quart, and maybe two or three, to fill it completely up.
You may have to repeat this process a couple of times to get all the air out (air can sometimes "hide" in the heater core and hoses).
