How to Install NTK Performance Oxygen Sensor - Rear on your Sierra

STEP 1: Remove protector cap just prior to installation

STEP 2: If not already coated, apply (enclosed) anti-seize to oxygen sensor threads

STEP 3: Install sensor body ensuring lead wire is not twisted or bent

STEP 4: Install all sensors with new gasket supplied & torque to proper specs as below:

M18 sensors - Install finger tight then 1/2 - 3/4 turn with wrench / O2 sensor socket 26-33ft. lbs.

M12 sensors - Install finger tight then 3/4 - 1 turn with wrench / O2 sensor socket 13.2-17ft. lbs.

a) Flanged applications- (where flange is NOT already installed on sensor) Install flange to exhaust manifold first, then mount sensor in flange (copper gasket is bonded to the flange & no additional gasket is required)

b) Flanged applications- (where flange is already installed on sensor) (It is important to use the supplied gasket before installing sensor)

STEP 5: Connect and route lead wire as originally installed