O2 Sensor-97 Tahoe 5.7L

cajun_lad

Active Member
Joined
Sep 3, 2007
Location
Vidalia, GA
Ok, I got 3 of the 4 changed out, but can't seem to get the last one to budge. Anybody got any suggestions? Yes, I've tried an O2 sensor socket and all it did was start stripping the corners down. In case anybody is familiar witht this particular setup, its the furthermost downstream sensor that's giving me probs.
 
spray with your penetrating liquid of choice, heat the area, repeat, let sit for a little while.. you can also try tapping the area with a hammer while loosening it... and I like to use a box end wrench sometimes.. you can hit that with a hammer...
 
7/8" box wrench like Rich said, the O2 sensor sockets spread out like you have seen. use them only for installing sensor.

Are you replacing the sensor because of a code SAYING bad sensor ? If so, you may want to do the intake gaskets soon, as the coolant leaking into the intake stream is probably what took them out, and you'll be looking for converters next.

Though if you got a catalyst low efficiency code your cats are already toast, and the sensors will be following also due to coolant. VERY COMMON in the "R" engine equipped 'Hoe's, 'burb's and trucks.
 
First I got codes saying both upstream were out, so I changed them, then a couple of weeks later I got another code saying the downstream were out. I haven't noticed any coolant disappearing so I don't know if I want to go tearing apart intake manifolds just yet. Especially since this is my DD. I thought I read somewhere that the O2 sensors were on the 100,000 mile to do list. My tahoe is a 97 with almost 140K, so I just figured they were due. But running on 3 good ones and 1 bad one has me concerned.
 
Solution:
I ended up taking a hacksaw and shortening enough to hammer a 7/8" 3/4drive socket on (had to hammer cause the nut was rounded by this point) and then using a pipe over the ratchet handle and it finally broke free.


Of course, I am still getting O2 sensor codes. Bad cat? I heard the EGR can give the same code as the O2 sensor, anybody know if this is true?
 
It depends what code is reading. There is no code for "bad upstream o2 sensor" So get a code number and get back to us

Like metioned earlier the intake leaks allllllllll the time and cause bad o2 sensors and ruins the cats
 
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