OK, I just did both of mine two weekends ago. Let's see if I can remember.

Tools needed:

• O2 sensor socket (sectioned / split deep socket)
• 3/8" drive rachet
• 3/8" flex head breaker bar
• 2' length of pipe to be used a breaker bar extension
• can of PB Blaster, Liquid Wrench, or equivalent
• 3" long 3/8" drive extension (optional)
• 3/8" universal joint (optional)
• 7/8" deep socket (optional)
• 10mm socket

Can't remember if I needed to use the universal joint, or the 3" extension.

First things first - spray down the O2 sensors with the PB blaster. If you can do it several times days before you actually start working on it, it would be best. You'll need to remove the front plastic belly pan / shroud to get a good shot at the front O2 sensor from underneath.

Disconnect the negative battery lead before starting work, because you'll be right next to the electrical fans and don't want them going off accidentally while your hands are right there.

Front:
Unplug the front sensor. Remove the bracket that holds the wire in place. The bracket is held on by one of the front side cover bolts. Give the O2 sensor one more shot of PB Blaster. Using the O2 socket and the flex head breaker bar, making sure that the socket is fully seated on the sensor, try to break loose the sensor. You may need to use the 2' pipe as extra leverage if it is really tight. It should break loose after that. Replace the flex head with the rachet, and continue to loosen until it is hand loose. Loosen and remove by hand from underneath. Replace old sensor with new one, ensure that there is anti-seize on the threads. (If using a universal sensor, cut old connector off and crimp onto new sensor wire.) Install and hand tighten new sensor from underneath. Then tighten snug from above with rachet. Reconnect connector, and reattach bracket with side cover bolt previously removed. Reinstall belly pan.

Rear:
Same as front, except no need to remove any wire brackets, and can only get to sensor from above.

Tips:

• It helps by putting on the O2 socket onto the sensor by hand, and then snapping on the flex head or rachet.
• O2 sensors mount 90 degrees to the engine (exactly, or almost exactly horizontal). Remember this so you don't tilt the socket and strip the old sensor head when removing.
• Can cut the O2 wires and use a 7/8" socket (not quite sure of the size, so confirm with someone else), but be prepared to reconnect wires if removal isn't possible. I chose not to cut the wire. O2 socket will still be needed for install of new sensor. Standard socket may be needed in place of O2 socket if sensor head gets stripped, because standard 7/8" socket is stronger than the sectioned O2 socket.
• If O2 sensor refuses to give, use more PB blaster, let it sit, and try again later. Try alternating between tighening and loosening.
• Front O2 sensor has a longer wire than the rear, and uses a rubber insulator on the bracket mount. Old rubber insulator may need to be split down the middle and reused if the new one is universal or does not come with one.
• Rear O2 sensor has no rubber wire insulator.

That's all that I can remember right now. Good luck.

 

total props. this is what im talkin about. very detailed and precise. thankx! :bowdown:

 

Note: if your sensors are the original OEM ones like mine were (ie: been there for almost 15 years!!), they will be VERY tight. I almost stripped the head on the front one using the O2 split socket ...so I'd very much recommend using a 22mm "deep" socket instead ...its a perfect fit, while the O2 sockets all seem to be 7/8ths and a bit sloppy. And, for the consideration of the next owner, use some anti-seize compound on the sensors when you put the new ones in.

 

Note: if your sensors are the original OEM ones like mine were (ie: been there for almost 15 years!!), they will be VERY tight. I almost stripped the head on the front one using the O2 split socket ...so I'd very much recommend using a 22mm "deep" socket instead ...its a perfect fit, while the O2 sockets all seem to be 7/8ths and a bit sloppy. And, for the consideration of the next owner, use some anti-seize compound on the sensors when you put the new ones in.

Mine were original OEMs with 116k miles on them. Both needed the breaker bar extension to get them loose, but in my opinion, the key was using the PB Blaster. I was leary about cutting the wires and using the deep socket, but was prepared to if needed. The split socket worked fine for me. You just need to be sensible and to know how much force to put on it - in other words, if you're using the O2 split socket and it's giving you resistance, don't stand (with 250 lbs) on a 3' breaker bar extension.

 

where can i find pb blaster?

 

where can i find pb blaster?

I don't know what auto parts stores you have where you are, but you should be able to find it there (for us in the Northeast - Auto Barn, Pep Boys, Auto Zone, etc.).

Liquid Wrench also works. My experience with these three, ranked in effectiveness from best to worst: PB Blaster, Liquid Wrench, WD-40. I hear that Kroil is supposed to be pretty good, but have never tried it.

 

WD-40 is possibly a last resort and far behind Liquid Wrench of which I think there are two grades. I cannot find PB Blaster in Canada.

 

Given the detail chuckee and digger went into for this post, one of those two should combine everything into a DIY. This question will come up again in the future and you guys did a great job here that should be saved. :thumbsup:

 

i changed my front one today but couldnt manage to get the rear out i started to strip it out and then stop to prevent further damage.... does anyone have suggestons...and if not how much would a mechanic change.

 

i changed my front one today but couldnt manage to get the rear out i started to strip it out and then stop to prevent further damage.... does anyone have suggestons...and if not how much would a mechanic change.

Did you then try the 7/8" deep socket? If not, then cut the sensor wire, ensuring that you have enough to splice it back together. If you have a small inspection mirror, you might want to see how bad the damage is back there. Then hit it again with the PB blaster or Liquid Wrench. Let it soak at least a day, and hit it several times that day. Then give it a shot with the 7/8" deep socket the following day.

Some people have said that running the engine and removing it while hot (after turning off the engine) may help because of the exhaust manifold heating up and expanding, but the sensor will also be hot, too. Torching the manifold would be best, but tough to do in the limited space.

In my opinion, a mechanic should charge around $25-$40 to change it, since you are providing the replacement part. Shouldn't take him longer than a 1/2 hour to do it. Ask around.

 

tanks alotn i found pb blaster i didnot know to wait a day after using it then try to take it of but i will try then tell you the results.

 

My neighbor just did mine in about 15 minutes. liquid wrench,bosch oxy,and that special wrench from O,riellys($10). It looked easy. good luck

 

i am afraid i am strippig out the bolt with the special socket do you think the 7-8 inch deep socket will fix this?

 

........And, for the consideration of the next owner, use some anti-seize compound on the sensors when you put the new ones in.

There should already be some "special" anti-sieze on the new sensors.

This special anti-sieze contains glass beads (silica). Do not remove or apply regular old anti-sieze over this.

As far as tools to remove the sensor, avoid 12-point sockets. Use a 6-point socket.

 

There should already be some "special" anti-sieze on the new sensors.

This special anti-sieze contains glass beads (silica). Do not remove or apply regular old anti-sieze over this.

As far as tools to remove the sensor, avoid 12-point sockets. Use a 6-point socket.

Depends on the the Sensor Manufacturer. NTK Sensors have the anti-seize already coated on it. Denso does not, but provides a little tube of it for the installer to coat it with. I do not know what Bosch provides.

Ditto on the 6-point (deep socket). Even though the split O2 socket is a 6-point, it is weakened by the slot machined into it, and can spread with enough force and therefore strip the head. A (regular deep) 6-point can also strip the head if it is not seated properly when force is applied.

 

the special wrench will save your wire and give you better leverage than 7/8 deep socket.(well worth the $10)heard it through the grapevine

 

any pictures please?

 

what is a "special wrench" exactly? and how bad does it get if i dont change the front oxygen sensor? sorry for the questions but im trying to get the stupid "check engine" light to go off already

 

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