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Coolant Flush DIY 1999 Buick Century 3.1L engine


New member
Buick Ownership
1999 Buick Century
Good Afternoon. I am wondering if anyone has done the coolant flush themselves and where is the engine block drain plug. I have found the petcock for the radiator however having difficulties locating the block drain plug. Only got about just over 4 litres of coolant from the radiator. The capacity is about just about 10 litres. Any help would be appreciated


Active member
Poplar Grove, IL
Buick Ownership
2000 Century
Based on rust, I was afraid to pop off my block drains. I had the manifold off, so I siphoned out from the head coolant passage. I also vacuumed out the heat exchanger, as well as draining the radiator and reservoir. Close enough for me!
Pedal Commander