I'm trying to change my O2 sensor to improve my milage(i think the current one is still stock). I even bought that socket for changing them, but I can't get the darn thing out of the exhaust pipe. I have a 3.1 so its in the exhaust by the pass side wheel. What the hell do I do to get it out? About 15 minutes ago I tried again and ended up snapping that metal cylinder at the end . I tried running it to heat it up, i tried wd-40, I need your help!!!

 

try some real penetrating oil. wd-40 is really just a lubricant, you need some pd blaster or something like that. also, i normally just use a wrench on mine, you can use an open end wrench or a box end, or even an adjustable.

 

On mine I used a vise grip and a 5 Lb mini sledge. just make sure your knocking CCW. Clounter Clock Wise.

 

Oh that special oxygen sensor socket SUCKS!!! The slit in the side will cause the socket to "open up" on the sensor. I borrowed my dad's once, and wedged the damn socket onto the sensor! The ends spread open and the socket got stuck. The thing is useless- especially b/c when the socket spreads open, you can (A) ruin the fitting and then you're screwed, and (B) all your strength isn't going to the fitting, it's getting lost in the socket.

I do one of three things, from the easiest to the hardest- depends on how hard the sensor's stuck in there.

1. This works well if your sensor isn't frozen. Just use a 13/16th inch box wrench on the sensor.

2. Get a deep 13/16th socket. Unplug the oxy sensor. Force the deep 13/16th socket over the oxygen sensor- yes you'll catch the wire in the open end of the socket, but it's no big deal. Then use a 1/2inch drive, 12 to 15" breaker bar to crack the sucker loose. One more edit: Of course, a 6-point wrench will do the least damage to the fitting, and more of your torque will be applied to the fitting.

3. LostInPlace, this is what you've got now! Crack the back of the oxygen sensor off with pliers, or a chisel, or a hacksaw (depends on who made the oxygen sensor) so you're left with "just" the nut sticking out of the exhaust. Put a short socket over what's left of the oxygen sensor. Make sure the socket's a 1/2 inch drive, and use a 1/2 inch drive breaker bar on it. Reason- The shorter the socket, the less chance for side-loading the fitting, and the more torque goes right to the fitting. Always use as short a socket as possible on ANY bolt/nut/etc.

Note too that I kept saying breaker bar; don't even bother with a 3/8th ratchet from a socket set. A 15" breaker bar (1/2 inch drive) is only $20 at Sears, and man, it's one hell of a useful tool.

Be careful when you re-thread the new oxygen sensor in. I always add extra anti-sieze to the threads. New sensors come pre-anti-sieze'd, but I add more. DON'T get any anti-sieze on the tip of the oxygen sensor!! It can contaminate your new oxy sensor. If you do slip and get some anti-sieze on the vented tip, wipe it away with paper towels until it's clean again. And BE CAREFUL not to cross-thread the exhaust pipe bung! When I first changed the oxy sensor back in '94, I thought I was so careful not to cross thread it- but I did. I fixed that by buying a new Y-pipe in '97. Well, that wasn't the original purpose for buying a new y-pipe, but it was an extra bonus!

Oh and I guess you know that you can drive the car, just tie any loose wires away from melting on the exhaust. It'll throw a service engine soon light, but if you're just going to Sears and back, no biggie... just don't cook the wire or it's connector on the y-pipe (been there, done that).

I promise to not edit this post any more.

 

This is all really helpful stuff. Seems like I'll be heading to Sears in a bit. Thanks

 

Before I go, I should probably know what a breaker bar is/looks like.. haha. So what exactly is this thing and how will it help?

 

basically a bar with a swivel head. hense breaker "bar" . It helps because it is typically longer then a socket wrench, and a box wrench. typically about 15-18" normal length, or longer if needed.
It helps you gain leverage. say 180Lbs for exerted over 18" easily doubles if not tripples or more.

 

13/16" combination wrench is my personal favorite for this... sometimes sockets don't have a point.. you can get a box end over the wire *real* easy.. and oxygen sensors don't strip readily, so even a 12pt has little probelm with 'em.

 

wow... good info... i think i might try this when i get back into town (travelin for work until 2nd week of august, but you guys don't really need to hear this, lol )

 

Tom, the O2 sensor is 7/8ths. Never seen a sensor that was 13/16ths.


And to the original poster, the sensor may be seized, in which case you are screwed. You can still get the sensor out but the threads in the exhaust pipe will come out with it.

 

well I went to Sears using a different car, bought the breaker bar, came back and realized I don't have any sockets that fit the bar.. so i use a regular wrench and socket and after a lot of tugging, it loosens up. I put the new one in, and as far as being 'seized' goes, I don't think it was since the new sensor took some effort to put in.

Thanks for everybody's help, I'm uber relieved that its all over -Rob

 

That's a perfect example of a seized sensor. You should be able to thread the sensor all the way in by hand.

 

So there's something wrong with mine? I would think that you shouldn't be able to thread it in completely by hand. I don't know what to do, everything seemed fine once I got the old sensor out... Anybody have experience with this kind of situation?

 

it sounds like yours was seized, but if you got the new one in and there's no exhaust leaking from it, then don't worry about it.

The real bad sensors will take most of the thread right out of the exhaust pipe, leaving you with nothing to thread the new sensor into.

 

Oops, thanks for the correction, Dan!! It's been a while since I've changed one out!

 

When I changed mine I had a heck of a time getting it out. Even after I broke the initial torque it was hard turning it out almost the entire way. Putting the new one in well it started by hand for the first few threads but after the most of the way I had to really crank on it! Not as hard as getting it out but still pretty hard the rest of the way. It all works fine with no exhaust least yet had it in for the better part of a year. I know that these are supposed to be install when the pipe is at least 120* so if it took you a while after taking it out and the pipe cooled down some that could explain a little of the difficulty getting it in. I dont think you really have anything to worry about as long as there are no exhaust leasks around the sensor.

 

I recently changed my oxygen sensor. I had never done this before and had a difficult time at first. I sprayed it with 'PB Blaster' a few times ... it didn't budge. Next day I sprayed it again, drove the car to get the pipe hot ... it didn't budge (using excessive force). Next day I sprayed it again, drove the car to get the pipe hot, bought the special socket ... it didn't budge. Then I found the solution.

The way I was easliy able to remove my oxygen sensor was to drive to Walmart and spend $12 on a propane torch. I heated the bung on the pipe for a minute, slipped on a large adjustable wrench, and it came off with minimal effort.

So ...
(1) heating bung with propane torch seems to be the real trick
(2) driving the car doesn't seem to get it hot enough
(3) the special socket isn't worth 10 cents
(4) excessive force, breaker bar, vice grips, or hammer is not required

A few weeks after I changed mine, I did my girfriend Cavalier. I heated it with a torch and easily took it off with a adjustable wrench in under 2 minutes.

 

the reason that driving the car to get the pipe hot doesn't work is that it heats up the sensor too. therefore, the bung trys to expand but the sensor expands too. remember, heat causes things to expand. heating the bung with a torch will concentrate most of the heat on the bung, expanding it 'away' from the sensor.

 

And, if all else fails, there's always the BFH.

 

I also had a lovely time changing my O2 sensor.

Mine was also frozen in the exhaust pipe. I took a Mapp gas torch, heated the bung until it was almost a dull cherry red and the sensor came out. Unfortunately, the threads from the O2 sensor were still in the bung. What I had to do was purchase an 18mm spark plug tap and chase out the threads insinde the bung.

If you encounter this problem make sure that the idiot at the auto parts store gives you a tap and not a thread chaser . Apparently these morons cannot distinguish the difference between the two.

 

keep spraying WD 40 or Valuecraft again, if you keep heating it up it will be difficult to take it out. Use your best wrench tool and try to move it for both directions, it will make the rust crack off.

 

WD 40 is a lubricant, not a penetrating oil, in other words...it will do little good if any. heat is the best bet for something like this.