I've got well over 100K on the original O2 sensors. No codes thrown yet, but mileage has dropped significantly lately (average 13mpg vs prior 16mpg just a few months ago) and all my other emissions and engine control sensors check out OK.

I'm all for preventative maintenance and wouldn't have a problem installing new sensors but these things are a PITA to get to. Additionally, with all the trouble I've read in other posts about getting the old one's off, I'm wondering if it's worth it to just (gasp) take it to the shop and have them install new ones.

I've already bought the sensors. Just wondering if I want to burn a Saturday afternoon on this.

Thoughts?

 

Does yours have 2 or 4 O2 sensors? Mine has 4 and I replaced the two pre-cat ones recently. From what I've read, only the pre-cat O2 sensors can affect how the engine runs (I don't know for sure if that is true or not).

I used Kano AeroKroil (let it soak on the O2 sensors overnight), as I read that it is the best, or among the best, for loosening rusty fasteners. The mechanic that helped me do the job was fully expecting to have to use a torch to heat the threads; he even went and refilled his torch tank before starting because he was sure he would need it. However, the Kroil did its job and no torch was needed. Both O2 sensors came out with an O2 sensor socket connected to a normal length 3/8" drive socket wrench.

The hardest part of the job was unplugging the driver side pre-cat O2 sensor, as the plug was up alongside the transmission and it was hard to reach up in there to unplug it. The passenger side was quite easy, and everything on that one can be done from under the hood. For the driver side, the O2 sensor could be wrenched on from through the wheel well, but to unplug it / plug it in, you had to get under the vehicle.

I don't know about the two post-cat ones. From looking at them when I was under there, they didn't look like too terrible of a job, but they would have to be done from under the vehicle.

 

I have two sensors. I've seen a number of posts referring to the AeroKroil. I'll see if I can get some and give it a go. I don't mind crawling around under the truck, it's the horror stories I've read about getting them out that concerns me.

 

Just replaced mine, had to use a four foot pipe on my 1/2" rachet to break the front one loose, soaked them with rust buster first a couple of times. Bought the O2 sockets which definately helped, used an open end wrench once they broke loose, it was easier.

Depends on how much money you want to save as to whether you do it or not. Sensors and sockets cost me about $95. Saw where someone said a mechanic was going to charge $300 to change a sensor. I only have one per cat and one post cat. If you do it yourself make sure to add anti sieze if your new sensors do not have it already.

 

I was charged $10 to change two O2 sensors, but my mechanic has been my mechanic since I started driving 20 years ago, and he's never charged me more than $100 in labor even if he worked all day on my truck (which would be $320 according to his official $40/hr rate). I helped some with the plugs, but his two employees did most of the work.

 

'aight. I'm gonna give it a go. Bought some AeroKroil. Will report back after this weekend.

 

I shot mine with PB blaster. I also chopped off the top part of the old sensor before I removed it, allowing me to get a regular socket over it and a little better leverage. I used the O2 socket to put the new one back in. With the socket and regular break bar I had no problems.