NTK 25510 Oxygen Sensor - Upstream

Direct-Fit Oxygen Sensor

NTK Direct Fit Oxygen Sensor 25510 is a specific-fit heated oxygen sensor built for direct replacement applications. It uses a threaded mounting design and a 3-wire configuration to match the original sensor layout on covered BMW applications.

As part of the NTK Direct Fit Oxygen Sensor line, this unit is engineered for accurate fit, form, and function. NTK draws on OE oxygen sensor manufacturing experience and extensive production testing to deliver a sensor that meets or exceeds OE specifications.

Key Features

• Heated oxygen sensor design for faster operating response
• Specific-fit application for direct replacement use
• Threaded mounting type for secure installation
• 3-wire configuration with 28.7500 wiring harness length
• 18.000 thread diameter for matched fitment

Detailed Description

NTK 25510 is a direct fit oxygen sensor for select BMW applications, including Fits 1988-1991 BMW M3, upstream and Fits 1985 BMW 318i, upstream. It is built as an OE-equivalent replacement for air/fuel ratio monitoring, with the correct heated sensor design and threaded installation style for the listed applications. This part number 25510 is intended for buyers seeking a direct replacement oxygen sensor for BMW M3 and BMW 318i applications where the original sensor uses the same configuration.

NTK is known for oxygen sensor manufacturing within the NGK family of products, and this line is focused on broad coverage and OE application technology. The sensor is manufactured and tested to support reliable operation and consistent signal output under normal engine management demands. This part cross-references Bosch (e.g., 13047, 13058) for the same application.

What It Is Used For

• Replacing a worn or slow-responding oxygen sensor
• Restoring air/fuel ratio feedback to the engine control system
• Addressing sensor-related drivability or emissions faults
• Correcting a damaged threaded sensor connection
• Replacing an OE-style heated sensor on the listed BMW applications

Installation Notes and Tips

Verify the upstream position and connector configuration before installation. Confirm thread diameter, harness length, and wire count against the original sensor to ensure proper fitment. Use the vehicle’s service procedure for sensor removal and installation, and inspect the exhaust bung threads before threading in the new sensor.

Quality Assurance

NTK states that its oxygen sensors are extensively tested during manufacturing and are built to meet or exceed OE specifications. The brand also emphasizes OE application technology and original equipment oxygen sensor manufacturing experience.