Oxygen Sensor on 2.5L

[dubnutts]

I have 2 O2 sensors one before the cat and one after the cat. I am thinking about changing them since they havent been changed since i owned the truck and i have had it for 5 years but the one before the cat is all rusted up and seized and im sure the one after the cat will be alot easier. So my question is do i have to change both or can i get away with just changing the easy one. Ill do both but if i dont have to why do it. Thanks all

 

[shadetree]

The one before the cat is the actual 02 sensor. The one after the cat is to tell if the cat is doing it's job. Tho they look rusted, sometimes the will come out fairly easy with a sensor socket. If you can break it loose, spray it with some lubricant, and work it back and forth to get the lubricant in the threads. If it is really stuck, you will have to heat the bung.shady

 

[Ranger44]

I'd only change them if they're bad. Remove them and see if there is any heavy black, white, grey, etc deposits on it.

Maybe hook a Multi-meter up to them. Check resistance, and voltage.

If they or one is bad, replace it.

For heavy rust......PB Blaster and a cheater bar.....

 

[CraigK]

dubnutts

You might be able to tell if the O2 sensor requires replacement simply by unplugging it.
You do not report any symptoms of a bad O2 sensor, but poor gas mileage can be one.

To remove my 20+ year old sensor, I cut and broke the long steel encased ceramic stem off so that I could get a short 1/2" drive 6-point socket on the nut part. Note that mine NEEDED replacing, so trashing it was not an issue. Then I broke it free using a 1/2" ratchet with an extender pipe. While it took a LOT of force to break it free, it finally broke loose cleanly. I do not think mine would have broken free if I had used either a 12-point socket, or a long socket. Your O2 sensor should have been installed with some sort of anti-seize thread compound.

CraigK

 

[Bryan22]

I just changed mine a couple weeks ago. PB blaster. Soak it walk away for a couple hours and take it out. The o2 sensor in my 94 came out with hardly any force at all. i used an open end wrench to break it loose and twisted it out by hand the rest of the way.

 

[dubnutts]

O2 sensor pissing me off

i sprayed both with a can each of penetrating oil and tried to break them loose and it started to strip the part that the socket goes on so i am just gonna heat them up and use a pipe wrench to get them off or any other ideas thanks