Bank 1 is the passenger side of your engine on your Mountaineer
Sensor 2 would be after the catalytic converter ( downstream )
The oxygen sensor for bank 1 sensor 1 for a 2000 mercury mountaineer is on the cylinder #1 side.
Bank 1 is the passenger side of the engine in a Mercury Mountaineer ( V6 + V8 ) Sensor 2 is after the catalytic converter ( downstream )
Bank 1 is the passenger side of the engine in your Mercury Mountaineer Sensor 1 would be close to the engine before the exhaust enters the catalytic converter ( upstream sensor )
Bank 2 is the drivers side of the engine in your Mercury Mountaineer Sensor 1 is between the engine and the catalytic converter ( upstream ) Sensor 2 is after the catalytic converter ( downstream )
Bank 2 is the drivers side of the engine in your Mercury Mountaineer ( V6 + V8 ) Sensor 1 is in the exhaust close to the engine before the exhaust enters the catalytic converter
Bank 1 is the passenger side of your engine Sensor 2 is in the exhaust after it passes through the catalytic converter ( downstream )
location bank 1 sensor 1
On a 2002 Mercury Mountaineer ( V6 and V8 engines ) Bank 2 is the drivers side of the engine Sensor 1 would be close to the engine BEFORE the exhaust enters the catalytic converter
Bank 2 is the drivers side of the engine sensor 1 is in the exhaust , close to the engine , before the exhaust passes through the catalytic converter
Try to picture this Bank 1 Sensor 1 Bank 2 Sensor 1 Catalytic Conv. Catalytic Conv. Bank 1 Sensor 2 Bank 2 Sensor 2
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Before the catalyst, driver side.