Hi, I want some information regarding HC and CO2 in Coolant (Car cooling system). As you know when the sealing (head gasket) between water jacket and combustion chamber fails, the engine smoke will enter cooling system which contains HC and CO2. I know that CO2 makes coolant acidic and reduces it's PH value. Engineers use this method to determine head gasket failures. My questions: Will CO2 makes coolant permanently acidic? or just temporarily? Will CO2 remains dissolved in coolant after some hours later when you switch off the engine? How much reduction of PH occurs when CO2 enters Coolant? If engine cools down and i drain a sample of coolant, is it still possible to see PH changes or maybe cold coolant makes the test invalid? What i want to do is that i poor new coolant into the car and measure it's PH. Then i drive the car for about 2 days and measure it's PH again. If the PH value reduces, does it mean that there is a head gasket leak? Thanks for your scientific explanations.