Oxygen sensor problem.....

[wiesket]

While changing the oxygen sensors on my truck I ran into a problem removing one of them. It appears that the threads are messed up on the side that I had a lot of problems with. My question is .....is there someone out there who knows what size tap I will need to clean up the threads before installing the new sensor? I don't want to have a similar problem if I have to remove it again.

 

[RonD]

I think they are the same as spark plug threads, M18 is the size

And it is not uncommon to have to clean or rethread the holes so "they" make a short tap/chase tool just to get into the usually tight spaces.

Google: M18 thread repair tool


On my '94 4.0l the passenger side O2 had actually unscrewed itself 1/2 way, this of course allowed air to be pulled in, O2 reads that as lean exhaust, so computer added more fuel and my MPG went down.
I had 300,000 on them so bought 2 new O2 sensors, that's when I found the one that was unscrewed, lol.
Oh well serves me right for not checking first, probably had another 100k on the old ones

 

[wiesket]

RonD thanks for the reply. I had called Auto Zone and the kid I talked to said that they had nothing that would do what I wanted to do. I did a Google for the M18 Thread Repair Tool and AA was listed. They actually had two different tools that would do the job. One was p/n 25124 for 6.99 that is the plug hole thread chaser that does both 18m and 14 m. The other is the 02 sensor thread chaser p/n25255 for 9.99. The 02 tool worked just fine. Thanks again for the info.

 

[RonD]

Good work