GM/ AC Delco O2 sensors, which ones?

dna9656 · August 1

2015 Silverado 5.3 LTZ. I have to install a new "Y" pipe (the cats are integral with the pipe) VIN: 3GCUKSEC2FG305725. Best advice from all the forums I have read is USE GM cats and O2 sensors. There are many GM/AC Delco sensors. Anybody know what I need? I have read applications for Right Rear, Left Rear, Right Front and Left Front, other apps say fwd and rear, heated and non heated. I have been told (but I do not believe it) that there are programmable O2 sensors. I don't even trust the Chevy parts book any more. So help would be greatly appreciated! I have a GM "Y" pipe/Cats.

newdude · August 1

21 minutes ago, dna9656 said:

2015 Silverado 5.3 LTZ. I have to install a new "Y" pipe (the cats are integral with the pipe) VIN: 3GCUKSEC2FG305725. Best advice from all the forums I have read is USE GM cats and O2 sensors. There are many GM/AC Delco sensors. Anybody know what I need? I have read applications for Right Rear, Left Rear, Right Front and Left Front, other apps say fwd and rear, heated and non heated. I have been told (but I do not believe it) that there are programmable O2 sensors. I don't even trust the Chevy parts book any more. So help would be greatly appreciated! I have a GM "Y" pipe/Cats.

There is only 2 part #s for all 4 sensors. The fronts are one number both sides, the rears are one number both sides.

12659516 is the front 2, 12657188 is the rear 2.

GM vehicles are VERY sensitive to aftermarket O2 sensors, and OEM y pipe important because your truck is CARB becuase you are in Washington state so aftermarket cats, unless they are CARB, will cause you catalyst efficiency problems.