1997 HB, 4wd, 4-cylinder - I need to know that thread size on pre-cat oxygen sensor.
So, my old one was crapping out, and I finally felt motivated to replace that SOB on monday. I get to uncrewing it, and the old sensor decided to leave a few threads behind and trash some manifold hole threads as well. I didn't realize my manifold hole was messed up until I destroyed the tip of my new replacement sensor. Goodbye $40 universal replacement.
I went to various hardware retailers selling taps and dies. Either none were big enough, or none seemed to be similar to my threads. (non metric) Tomorrow, I'm going to have one last try at finding a proper tap to clean up that stupid hole. It's either that, or find a shop that has the ability to helicoil this hole for less than $80.
I can't find a size in the service manual, or by doing a search. And I don't have a gauge to check it off of the replacement sensor. Helicoil has kits for M18x1.5 threads or M18x1.4 threads. The kits are $80, but I don't need a kit that will repair 12 holes. Just one. Trying to be smart with my cash, ya know. In the mean time, I'll keep commuting a few miles to work with the old dead sensor with snipped wires in limp-home mode. As long as I minimize my trip distances, my cat will probably survive the extra fuel the truck is dumping down its throat.
So again, does anyone definitively know know the thread size?
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Mr. Pete
1997 Hardbody 4x4
1989 Prelude 2.0 Si
The threads on the sensor are verified as metric. 18x1.5 (18mm hole, 1.5 threads/mm). With the proper tap, and some oil, I cleaned up the hole and fit in the new sensor. There is no replacement for the proper tool....and a little bit of patience. Good thing too, since right after buying the tap, the manifold plug (dead sensor) decided to fall out in the street while driving. That left my truck sounding like I had a 18mm hole in the exhaust.....oh wait.
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Mr. Pete
1997 Hardbody 4x4
1989 Prelude 2.0 Si
Glad to hear you fixed it. I'm pretty sure that the O2 sensor hole is actually threaded into a larger spacer that then screws into the exhaust manifold. Not sure on the truck, but my Q had this... One sensor was seized into this spacer, but the whole thing screwed out of the manifold. I was able to order a replacement spacer cheap... in fact they accidentially threw a box of six into my shipment... so if anyone out there ever reads this thread PM me and I'll send you one!
Heath
__________________ 1997 Nissan XE Truck - 133,000 Miles
1990 Infiniti Q45 - 91,000 Miles
2005 Infiniti G35 Sedan - 34,000 Miles
You're probably right. There seemed to be a large spacer/bung which I assumed also was removable. However, I'm betting it would probably be a bigger whore to break loose than the sensor itself. Plus I don't think I have a socket large enough to get at it. Though it is something to keep in mind just in case. The alternative being the replacement of the entire mainfold. (and that too would probably have it's own twisted off bolts.)
Oh, fwiw, after my install, I did see NGK O2 sensors available online for only a few bucks more than bosch universal (cut and splice) sensors, and like 10 less than bosch OEM.
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Mr. Pete
1997 Hardbody 4x4
1989 Prelude 2.0 Si
That was the site. I just bought some plugs and wires from there too. And I was able to track down a coupon code from another forum. My mileage isn't terrible ~ 22 mpg for a 4x4, and most of my driving is below 55.
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Mr. Pete
1997 Hardbody 4x4
1989 Prelude 2.0 Si
Linear Mode
