o2 sensor ( downstream) STUCK!!!!!

**mtnman** · 03-20-2013

Hello there. Im new to the site and bin looking around quite a bit and im very impressed with the info on here.
Im am having a hell of a time getting the o2 sensor out of the cat pipe on my 99 gran prix GT. it is stuck and when i mean stuck I mean I broke my o2 sensor socket and then busted a pipe wrench in half trying to get it out after my regular deep well rounded it off. Im running out of sensor to work with. AND PATIENCE! Any Ideas? Im thinking of drilling a new hole and welding a nut onto the pipe and just installing the new one next to the original one. how much of the bottom of the sensor needs to be exposed to exhaust fumes? Thanks for any help you all might be able to give.

**MoarkatsINmuhtrailer** · 03-20-2013

Have a straight piece of pipe welded in place of the "u-bend".

Then weld an o2 bung on the side of it for the o2 sensor.

**Slick2500** · 03-20-2013

This ^ depending on the shop shouldn't cost you too much.

**mtnman** · 03-20-2013

does getting rid of the U bend make much difference? I thought about that but I was wondering if the U was there for some reason like maybe back pressure or some thing.

**MoarkatsINmuhtrailer** · 03-20-2013

1. Backpressure is a myth...Don't worry about that nonsense.

2. The ubend was put there by GM so they could put the o2 sensor straight up to protect it from road debris.

3. It will actually help you get alittle more flow in the downpipe from removing it.

**Scottydoggs** · 03-20-2013

ive always been a fan of vise grips and a hammer lol not kidding. once the nut is rounded what more is there?

cutting the U bend out and mounting the o2 bung sideways will work if it don't come out.