Contour Enthusiasts Group Archives Forums General Troubleshooting Oxygen Sensor Hell

I'm having a devil of a time removing a bad 02 sensor on this Contour 4-banger. The hex part got rounded off even using the correct tool. It is that frozen/stuck.

I soaked it with penetrating oil and tried heating it with a propane torch but no go.

Now I'm trying to get the heat shield off and maybe try to get a vice grip on it. Of course the lower right heat shield screw is really tight and I'm worried about snapping it off (it is soaking overnight).

Anyone have this problem besides me? If so, how did you finally get the 02 sensor out?

As a last resort I'll have to try and beat it loose with a hammer and chisel.

Oh joy!

Nobody has any advice or encouragement for me?

Am I the only one to experience it?

I could at least use a pat on the back. This little procedure is turning into a nightmare!

Thanks....

It sounds like you've already done what I would have suggested. I had some stuck/rusted bolts on my exhaust. I sprayed penetrating fluid on them several times over a few days and then used a propane torch. They finally came loose.

Well, I propane torched the lower RIGHT heat shield bolt boss on the exhaust manifold and SLOWLY it turned out without breaking. Never screeched but felt exactly like the bolt was twisting/tearing in half but it didn't and came out intact.

Whew!

But I'm still not in the clear. The lower LEFT heat shield nut that came off isn't the whole story. There's also a threaded stud that screws into the manifold that also has to come off to remove the heat shield.

Curses!

Of course I don't have a 13mm deep socket in my toolbox and the local hardware store doesn't have it either (very rural district), so it looks like another online order to AutoZone.

Funny, but AZ doesn't seem to have 3/8" drive sockets, but 1/2" drive should be okay.

Maybe I'll look at my spark plugs and wires and see if they need changing too. Seems like in the records that came with this car it was lots of miles since they were last changed and it does idle poorly.

Anyone know if the "DoubleSilicone" brand ignition wires are okay? They are $30. Not the lowest buck which are $20, nor the highest which are $36 (Bosch).

I do feel better after getting that one bolt out without breaking it.

Thanks!

02 Sensor HELL Update:

My 95 Contour sat while I waited for a 2nd online order from AutoZone with a 13mm deep socket. The order came FAST and yesterday with warmer weather I tackled the project of removing the stubbornly STUCK 02 sensor once again.

With some heat and my new 13mm deep socket I got the lower left stud off that was holding the heat shield on. Went well!

Thank you AutoZone and FREE SHIPPING to my rural doorstep!

Then, with a little wiggling movement the heat shield was OFF and I could FINALLY get at the badly stuck and MANGLED 02 sensor!

The idea of using a vice grip on it was a sick joke. You couldn't dream of getting any solid grip on it. Plus a vice-grip would have bent in half anyway. Hopeless. So, I used the only other option I could think of:

BRUTE FORCE!

Yes, I got out the chisel and the BFH. Actually first I tried applying heat and using a small hammer and drift. But the exhaust manifold just sucked up all the heat my little propane torch could put out and the stuck 02 sensor just ignored the little hammer and drift like they were love taps!

So then I got a big long sharp cold chisel and a BIG hammer. I then proceeded to cut a deepish groove on the left side of the mangled 02 sensor hex for a solid spot to hit. Then, using a long flat-nosed drift and the BFH I proceeded to strike at the 02 sensor in a counter-clockwise direction with greater violence.

No go.

Not a budge!

More Liquid Wrench.

Grit my teeth.

More hitting...HARDER this time!

Still nothing....

I started to sweat and feel nervous as this was my LAST HOPE!

Then I began to really SLAM the BFH against the drift!

WHAM! WHAM! WHAM!

The groove started to deform....pieces of metal came off the 02 sensor....altho it was good tough steel....not soft!

I stopped and wondered if I should call it quits for the day, but then decided to go for it and recut the groove a little bit more.

Then I took a deep breath and literally POUNDED on the drift with all my might!

BOOM! BOOM! BOOM!

I was afraid that with each blow the manifold would either crack or the 02 sensor would break off or at least the striking groove would spall off completely and then I'd be in DEEP s__t.

Then, like a MIRACLE it "seemed" like the drift subtly shifted its striking angle!

Was I imagining it or was it really happening?

I hit some more moving the drift a little counterclockwise with each strike. OMG, it "seemed" to be turning!

More LW and more hitting:

YES IT WAS TURNING!

A minute later I had the rusty mangled freaking nasty 02 sensor totally off at last after WEEKS of worry, doubts, and struggle!

More miracles: No cracked manifold. Threads intact!

I felt happy all afternoon: giddy; giggly!

I feel that way again typing this....

VICTORY AT LAST!

The 02 sensor that came out is marked:

"Ford 94BB-9F972-DA NTK Japan"

Is this the ORIGINAL stock 02 sensor that came with the car when new in 1995? Anyone know? I suspect it is because I have lots of repair records and no 02 sensor is listed and they stopped taking it to a stealer early in the car's history and from the way that baby was STUCK SOLID and with a "94" Ford part number on it...hmmmm...I just wonder????

The moral of the story is: Don't give up no matter how much you feel that you are stumped. Of course I had the luxury of another car while this thing sat. Plus the SHAME I would have felt taking it to a mechanic who might have said when he saw the MANGLED 02 sensor: "Tried fixing it yourself, eh?"

Thanks for listening.

I just had to share this adventure in Contour Repair Land!

I would have recommended a pipe wrench in that situation, if you had the space. Congrats on getting it off though!

Glad you finally got it off. Be sure and use anti-seize on the threads if you think you might ever have to remove it again.

I shall celebrate this GREAT VICTORY over the Forces of Rust and Stealership Darkness by adding a 2nd VERY COOL looking 1976 Toyota Corona wheel cover to my Contour.