O2 sensor stuck

groovydude · 09-18-2015, 10:28 AM

I'm trying to replace my O2 sensor. The old one won't budge. I have the tool that our host sells. I've tried adding a pipe over the handle of my drive for more leverage, and I've reached the point where more force seems like a bad idea. I've also tried a few drops of liquid wrench around the nut. Any suggestions?

darrin · 09-18-2015, 10:32 AM

I have no first=hand experience, but have seen posts referencing the need to apply heat to get the O2 sensor off. In response to one poster's discussion of using a propane torch to do this, another suggested simply driving the car to get it up to operating temp (which would get the cat/o2 sensor hot) and trying to remove after hot

word · word's Garage

Soaked mine overnight (twice) in PB blaster then used a propane torch and the pipe over the wrench trick.

gazzerr · 09-18-2015, 10:54 AM

I had to soak mine in PB Blaster for a day because the washer under the sensor was badly corroded nicely locking the sensor in place. It came off with an extension bar.

Targa Me · Targa Me's Garage

Just add a little bit of heat from the propane torch will do the trick. Or drive it, as someone suggested. Either way heat works.

Bob Kontak · Bob Kontak's Garage

Quote:

Originally Posted by Targa Me

Just add a little bit of heat from the propane torch will do the trick. Or drive it, as someone suggested. Either way heat works.

Heat +1 but leverage helps as well.

The O2 sockets are long and 3/8 drive. If you grind the neck of the O2 sensor off above the 7/8's hex you can position a shortie 7/8" half-inch drive six point socket on the hex with a breaker bar. Optimally, a six point box wrench with a cheater bar.

You can buy the DIY O2/Propane or Map gas torches at Lowes or Home depot. Plenty of heat for this job but the $10 O2 bottles are gone after about six bolts you turn red. All-in, about $100.

gazzerr · 09-18-2015, 12:03 PM

Wouldn't take long before you may as well just pony up and buy a small oxy/acetylene rig. Good to know.

groovydude · 09-18-2015, 12:51 PM

It seems to me like heat would make the exhaust pipe expand, which would cause it to tighten up on the sensor?

I really hope I'm not forced to grind any part of my O2 sensor just to get it off. Yuk.

bpu699 · 09-18-2015, 12:58 PM

If you intend to replace the 02 sensr, just break off the exposed portion, and use an impact gun. Works great. You still have to soak it multiple times, and drive it in/out bit by bit. O2 sensors are pretty cheap nowadays...

Bo

darrin · 09-18-2015, 01:03 PM

Quote:

Originally Posted by groovydude

It seems to me like heat would make the exhaust pipe expand, which would cause it to tighten up on the sensor?

I really hope I'm not forced to grind any part of my O2 sensor just to get it off. Yuk.

why don't you try a combination of soaking with pb blaster and trying to remove with a breaker bar immediately after getting it nice and hot while driving. Doesn't seem that there's anything to lose this way.

I believe that the heat is helpful because of the different expansion/contraction properties of materials used to make the sensor and cat. i.e. the exhaust pipe and sensor expand (and contract) at different rates.

groovydude · 09-18-2015, 01:57 PM

I felt a little give, so I figured either it moved a bit or the threads were starting to strip. Turns out it's the latter. Once I start to destroy the O2 sensor just to get it out, I'm committed, and I don't have an impact drive, which is probably what I need once the top is off, so I might just drive it down to the mechanic while I can still drive the car. This was supposed to be an easy job - yeah, right.

Bob Kontak · Bob Kontak's Garage

Quote:

Originally Posted by groovydude

II really hope I'm not forced to grind any part of my O2 sensor just to get it off. Yuk.

Yep, it's yukky. Ceramic inside, which is tough to grind.

Work on becoming "one" with the yuk, it will save you squillions.

tirwin · tirwin's Garage

Another tip is after penetrating oil and heat, put an ice cube right on the hot metal of the nut or O2 sensor in this case. Sometimes the cold shock helps.

gazzerr · 09-18-2015, 08:07 PM

Like some of the guys have suggested I'd heat up the metal around the sensor. That should bust up the corrosion and open up the surrounding metal enough for you to get it off.

groovydude · 09-23-2015, 07:54 AM

Days of trying and it's still stuck. And I'm wearing out the nut. Someone pointed out that the washer seems to be missing, my guess is that the mechanic who installed it forgot the washer and overtightened to compensate.

gazzerr · 09-23-2015, 10:42 AM

Have to tried to heat it up around the sensor?

groovydude · 09-23-2015, 11:11 AM

Yes. No dice. I soaked the nut for two days with penetrating oil and PB blaster. The sensor in there probably isn't bad, but I don't know when it was last replaced, and I'm trying to get the car up to date with all routine maintenance.

gazzerr · 09-23-2015, 11:27 AM

Might have to take it to an exhaust place where they can bust off the top, heat it up cherry red and use an impact gun on it. My washer so so rusted you couldn't tell there was one on there until the sensor came off.

vascott01 · 09-23-2015, 11:44 AM

I had a hell of a time getting mine off...but patience does pay off

I used ATF and acetone equal parts on it.. Aero Kroil is another great product for similar jobs

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When you attach the socket and wrench use a hammer on it...trying to pull will surely strip the threads and cause you to seal it up and have another Bung installed