using a universal overflow bottle. I have the coolant line ran to the bottom of the tank. The tank has the cheap flip up cap for a lid. Do I need to add a hole for venting or is it fine?
overflow? You need one because when the engine gets hot the coolant expands and will begin to overflow and if you dont have a recovery tank it will do two things- one piss out coolant all over the ground and then when the motor cools down the coolant actually is sucked back into the radiator. If you dont have the overflow you run the risk of low coolant. in the radiator and overheating
because if the car overheats where is the excess coolant going to go if you dont have a vent tube. It is also to help vent the excess pressure so the radiator or overflow doesnt go boom