02 sensor

Oxygen O2 Sensor

BMW Models	E34, E31, E32, E28, E24
Difficulty	AVERAGE
Price estimate	$80 to $200

The BMW Oxygen sensor measures the amount of oxygen in the exhaust after combustion and signals the computer to adjust the air/fuel mixture.

Symptoms

• oor performance, poor fuel economy and high emissions are the failure syndromes.
• Check this great O2 sensor FAQ.

Procedure

• 02 sensor socket (can be purchased at Autozone)
• Lot's of WD-40
• Ratchet, extensions and u-joints
• Anti seize compound

Place the front of the car on jacks or use a ramp, then spray the old sensor with a lot of WD40 (with cold exhaust). Let it sit for awhile then you can remove the sensor with the sensor socket some extensions and u-joints. Don't forget to apply a coat of anti-seize compound on the new sensor threads. NOT on the tip!!!

In any model, you don't have to remove any part of the exhaust line.

525i

M20 : The O2 sensor is located below the #6 cylinder on the front of the exhaust pipe. The connector is located on the right-hand rear of the engine, near the electronics box.

M50 : The O2 sensor is located at the front of the catalytic converter. The connector is located on the left-hand side of the engine, below the starter.

530i - 540i

The M60 engine uses two O2 sensors located at the front of the catalytic converters.
The connector is located beneath the car under the transmission.

535i

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The 535i uses a single O2 sensor located at the front of the catalytic converter under the car. The connector is located at the rear of the engine compartment, lower left-hand side. (Round plug)

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