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OnlineHelp
OnlineHelp, Mechanic
Category: Car
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Experience:  Mechanic
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how do you replace a O2 sensor on a 97 chevy blazer

Resolved Question:

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Submitted: 8 years ago.
Category: Car
Expert:  OnlineHelp replied 8 years ago.

Hello and thank you for choosing Just Answer.

There are 4 different oxygen sensor on your car. Two are mounted on the exhaust manifold and 2 are mounted right after the catalytic converter.

Removal & Installation

WARNING

The sensor uses a permanently attached pigtail and connector. This pigtail should not be removed from the sensor. Damage or removal of the pigtail or connector could affect the proper operation of the sensor. Keep the electrical connector and louvered end of the sensor clean and free of grease. NEVER use cleaning solvents of any type on the sensor!

The oxygen sensor may be difficult to remove when the temperature of the engine is below 120°F (49°C). Excessive force may damage the threads in the exhaust manifold or exhaust pipe.

Oxygen sensor-4engines

Oxygen sensor-4.3L engines

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Oxygen sensor-5.0L and 5engines

Oxygen sensor-5.0L and 5.7L engines

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Oxygen sensor-7engines

Oxygen sensor-7.4L engines

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  1. Unplug the electrical connector and any attaching hardware.

  2. Remove the sensor using an appropriate sized wrench or special socket.

To install:

  1. Coat the threads of the sensor with a GM anti-seize compound, part number(NNN) NNN-NNNN or its equivalent, before installation. New sensors are usually precoated with this compound.

The GM antiseize compound is NOT a conventional anti-seize paste. The use of a regular paste may electrically insulate the sensor, rendering it useless. The threads MUST be coated with the proper electrically conductive anti-seize compound.

  1. Install the sensor and tighten to 30 ft. lbs. (40 Nm). Use care in making sure the silicone boot is in the correct position to avoid melting it during operation.

  2. Engage the electrical connector and attaching hardware if used.

WARNING

The sensor uses a permanently attached pigtail and connector. This pigtail should not be removed from the sensor. Damage or removal of the pigtail or connector could affect the proper operation of the sensor. Keep the electrical connector and louvered end of the sensor clean and free of grease. NEVER use cleaning solvents of any type on the sensor!

The oxygen sensor may be difficult to remove when the temperature of the engine is below 120°F (49°C). Excessive force may damage the threads in the exhaust manifold or exhaust pipe.

  1. Disconnect the negative battery cable.

  2. Unplug the electrical connector and any attaching hardware.

  3. Remove the sensor.

To install:

  1. Coat the threads of the sensor with a GM anti-seize compound, part number(NNN) NNN-NNNN or its equivalent, before installation. New sensors are precoated with this compound.

The GM antiseize compound is NOT a conventional anti-seize paste. The use of a regular paste may electrically insulate the sensor, rendering it useless. The threads MUST be coated with the proper electrically conductive anti-seize compound.

  1. Install the sensor and tighten to 30 ft. lbs. (40 Nm). Use care in making sure the silicone boot is in the correct position to avoid melting it during operation.

  2. Engage the electrical connector.

  3. Connect the negative battery cable.

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