Where is O2 sencer on 1998 Chevy Blazer?

The location of the O2 sensor(s) on a 1998 Chevy Blazer depends on the engine. There's usually one upstream (before the catalytic converter) and one downstream (after). They're typically threaded into the exhaust manifold or exhaust pipe.

To find them, you'll need to:

1. Identify your engine: Look for a sticker under the hood that indicates the engine size (e.g., 4.3L, 5.7L). This will help you find a diagram specific to your Blazer.

2. Consult a repair manual: A Haynes or Chilton repair manual for your specific year and model Blazer will have detailed diagrams showing the exact location of the O2 sensors. This is the most reliable method.

3. Use an online parts catalog: Websites like AutoZone, Advance Auto Parts, or Napa Auto Parts allow you to select your vehicle's year, make, and model, and then view diagrams showing parts locations, including O2 sensors.

General locations (but not guaranteed for your specific engine):

* Upstream O2 sensor: Often located on the exhaust manifold, close to the engine.

* Downstream O2 sensor: Usually located on the exhaust pipe, after the catalytic converter.

Without knowing your specific engine, I can't give you a precise location. Using a repair manual or online parts catalog is essential to accurately locate the O2 sensors on your 1998 Chevy Blazer.