downstream oxygen sensor replacement help!

[guitarguyucf]

So im at my wits end! I Got the 3 piece tool kit from Autozone and used the 7/8 which worked perfect for the upstream sensor. Basically the lower one is fused with the exhaust system and even after 4 soakings of pb blaster and wd-40 it wont budge...any suggestions???

[kfish]

big ol breaker bar

[silverstreak]

big ol breaker bar

^ that and heat

[guitarguyucf]

Is it all that necessary to replace the downstream one? I did the upstream one because I had poor gas mileage, and figured I would just do both...but seriously i cant get this thing off and wondered if its worth the hassle?

[matt5112]

no...

all it does is monitor the health of your cat.

[JoshMcMadMac]

Kroil...and heat. Also, try working it a touch tighter before rocking to looser.

[kfish]

put a pipe on the handle of the breaker bar to extend it some more if need be. itll come out.

[OH4CompG]

Once it pops and breaks loose the corrosion it'll come out. Just be careful and work it back and forth with pb blaster.