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NTK 21500 Oxygen Sensor - Upstream
| Brand | NTK 21500 |
|---|---|
| Position | Upstream |
| Wiring Harness Length | 7.0000 |
| Sensor Type | Non heated |
| Universal Or Specific Fit | Specific |
| Wire Quantity | 1 |
| Thread Diameter | 18.000 |
| Mounting Type | Threaded |
| Product line | Direct Fit Oxygen Sensor |
| Fits | Cadillac · 4 vehicles |
Direct-fit design. Built for specific applications with a threaded mounting style.
Non-heated sensor. Uses a one-wire layout with a 7-inch harness for application-specific routing.
OE-level testing. Extensively tested during manufacturing to meet or exceed OE specifications.
Cross-references Four Seasons 12006, 75-1503 and 213-630 for the same application. See all 7.
Will it fit your vehicle?
Free return shipping if it doesn't fit.
Direct-Fit Oxygen Sensor
NTK 21500 is a direct-fit oxygen sensor built for specific applications and engineered for threaded installation. It uses a non-heated design with a 7-inch harness and 18 mm thread diameter for a precise replacement profile.
- Direct-fit oxygen sensor for specific applications
- Non-heated sensor design with threaded mounting
- 7-inch wiring harness for application-specific routing
- 18 mm thread diameter for the correct exhaust bung size
Fitment Details
Compatible with 1979-1980 Cadillac Eldorado, upstream. Compatible with 1979-1980 Cadillac Seville, upstream. This part cross-references Four Seasons 12006 for the same application.
What It Is Used For
- Replacing a worn or slow-responding oxygen sensor
- Restoring accurate exhaust oxygen feedback to the engine control system
- Addressing sensor-related drivability or emissions concerns
- Correcting fitment issues caused by an incorrect sensor style or thread size
Installation Notes and Tips
Use the threaded mounting style and harness length to confirm application match before installation. Verify the upstream location and 18 mm thread diameter against the original sensor on the vehicle. NTK 21500 is a specific-fit replacement, so matching the exact application is important for proper installation.
Quality Assurance
NTK is part of the NGK family and is recognized as a major original equipment oxygen sensor supplier. Each sensor is extensively tested during manufacturing to support OE-level fit, form, and function. Part number 21500 is built to meet or exceed OE specifications.
| Year | Make | Model | Liters | Cylinders | Fuel Type | Position | Notes |
|---|---|---|---|---|---|---|---|
| 1980 | Cadillac | Eldorado | 5.7L | V8 | GAS | Upstream | Equivalent OE design oxygen sensor; Direct Fit Oxygen Sensor |
| 1980 | Cadillac | Seville | 5.7L | V8 | GAS | Upstream | Equivalent OE design oxygen sensor; Direct Fit Oxygen Sensor |
| 1979 | Cadillac | Eldorado | 5.7L | V8 | GAS | Upstream | Equivalent OE design oxygen sensor; Direct Fit Oxygen Sensor |
| 1979 | Cadillac | Seville | 5.7L | V8 | GAS | Upstream | Equivalent OE design oxygen sensor; Direct Fit Oxygen Sensor |
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