NTK 25571 Oxygen Sensor - Upstream
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NTK
 Direct Fit Oxygen Sensor

NTK 25571 Oxygen Sensor - Upstream

Brand NTK 25571
Position Upstream
Wiring Harness Length 36.7500
Sensor Type Heated
Universal Or Specific Fit Specific
Wire Quantity 4
Thread Diameter 18.000
Mounting Type Threaded
Product line Direct Fit Oxygen Sensor
Fits BMW · 3 vehicles

Direct-fit design. Built for specific applications with OE-style fit, form, and function.

Heated sensor. Helps the sensor reach operating temperature for responsive exhaust feedback.

OE-focused engineering. NTK tests each sensor during manufacturing to meet or exceed OE specifications.

Cross-references Bosch 13069 and 11781734796 for the same application. See all 2.

$152.91Free shipping
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Direct-Fit Oxygen Sensor Overview

The NTK 25571 is a direct-fit heated oxygen sensor for specific BMW applications. It is built with a threaded mounting design and a 4-wire configuration for accurate exhaust feedback in the emissions system.

As part of NTK’s Direct Fit Oxygen Sensor line, this sensor is engineered for OE-style fit, form, and function. It is a strong match for BMW 318i and BMW 318is applications that require an upstream oxygen sensor with the specified harness length.

  • Heated oxygen sensor for faster operating response
  • Specific-fit design for direct replacement use
  • Threaded mounting type for secure installation
  • 4-wire configuration for signal and heater circuit operation
  • 36.7500 wiring harness length for the listed application

Fitment Details

Fits 1991-1992 BMW 318i, upstream.

Fits 1991 BMW 318is, upstream.

This part cross-references Bosch 13069 and BMW 11781734796 for the same application.

What It Is Used For

  • Replacing a worn or slow-responding upstream oxygen sensor
  • Restoring proper exhaust gas feedback to the engine management system
  • Addressing oxygen sensor fault codes related to heater or signal performance
  • Correcting drivability issues tied to inaccurate air-fuel mixture control

Installation Notes and Tips

Verify the upstream location, connector style, thread diameter, and harness length before installation. The 18.000 thread diameter and threaded mounting type must match the vehicle’s sensor port for proper fitment. Use the listed BMW application data to confirm compatibility with the exact model year.

Quality Assurance

NTK is a major original equipment oxygen sensor supplier and tests these sensors during manufacturing to meet or exceed OE specifications. The 25571 is backed by NTK’s OE-focused engineering and application coverage.

Related reading

This part fits 3 vehicles
Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.
YearMakeModelBody TypeLitersCylindersPositionNotes
1992BMW318iConvertible1.8LL4UpstreamB1S1; Sensor w/940mm Length; OE Equivalent Design; Direct Fit Oxygen Sensor
1991BMW318i—1.8LL4UpstreamB1S1; w/940mm Length; OE Equivalent Design; Direct Fit Oxygen Sensor
1991BMW318is—1.8LL4UpstreamB1S1; w/940mm Length; OE Equivalent Design; Direct Fit Oxygen Sensor
Directly replaces or cross-references 2 part numbers
Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.
Bosch — 1306911781734796