DanPerryy
Well-Known Member
The stock cobalt has a closed coolant system with the pressure relief cap in the coolant reservoir tank. There is no radiator cap on the radiator.
The cap on the coolant reservoir tank has a pressure relief valve to vent for excess pressure AND a vacuum vent to draw air in for low pressure. The Goblin's radiator has a radiator cap. This cap too will relieve excess pressure. However which of the two caps (radiator, reservoir) relieves pressure first is a guess. That is not a problem BUT the "extra" vacuum vent on the radiator cap is a problem. Which of the vacuum valve actuates first is a problem. If the radiator cap activates first you have just put an air "bubble" in your sealed coolant system and the "bubble" has to be "sucked" through the system to the engine water pump and then the bubble can be discharged back into the reservoir through the small hose from the top of the head ( the little pipe running parallel with the fuel rail).
The simple solution is to close the coolant system like the stock Cobalt. This is easily done by capping off the little overflow vent on the radiator so it can't expel coolant or draw air into the radiator. As a closed system, it does not matter the direction for flow through the radiator (top to bottom or bottom to top). The Cobalt flows from side to side of the radiator.
The cap on the coolant reservoir tank has a pressure relief valve to vent for excess pressure AND a vacuum vent to draw air in for low pressure. The Goblin's radiator has a radiator cap. This cap too will relieve excess pressure. However which of the two caps (radiator, reservoir) relieves pressure first is a guess. That is not a problem BUT the "extra" vacuum vent on the radiator cap is a problem. Which of the vacuum valve actuates first is a problem. If the radiator cap activates first you have just put an air "bubble" in your sealed coolant system and the "bubble" has to be "sucked" through the system to the engine water pump and then the bubble can be discharged back into the reservoir through the small hose from the top of the head ( the little pipe running parallel with the fuel rail).
The simple solution is to close the coolant system like the stock Cobalt. This is easily done by capping off the little overflow vent on the radiator so it can't expel coolant or draw air into the radiator. As a closed system, it does not matter the direction for flow through the radiator (top to bottom or bottom to top). The Cobalt flows from side to side of the radiator.
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