1996 Mark VIII Runs Hot, But Coolant Overflow Tank Cool

[driller]

Without the t-stat you will not be 'closing' the bypass on the cooling system and subsequently you will not have full flow through the radiator. The bypass allows the water pump to circulate coolant through the block 'bypassing' the radiator until the t-stat opens. As the t-stat opens, the bypass closes.

 

[Teadt]

Wow, great break down, thank you

 

[psychostang]

Plus, it doesn't allow the coolant to stay in the radiator long enough to cool.