It took me the better part of 2 hours to remove the old O2 sensor and I finally had to settle on removing the adapter that it threads into. Of course the old one is destroyed and won't even lock down anymore. The threads are beat. I guess 13 years and 400K km have taken their toll.
Is this part replaceable from the dealer or do I have to order a whole new exhaust manifold. It looks like a pipe reducer one might find at a hardware store for nat gas lines. Should I bother looking or is it *special*
What you are experiencing is the result of someone not applying anti-seize compound when installing the sensor. When you sort out your situation, and install the new parts make sure you use anti-seize compound when installing threaded parts where there is substantial heat involved (exhaust manifold), or either threaded part is aluminum, magnesium etc., even if there isn't high heat involved (sparkplugs in an aluminum head).
The threaded part that came out with the sensor is likely a reducing bushing with pipe or tapered threads. The bushing should be available from a Nissan dealer, or for a cheaper cost and likely quicker availability check with a full service hardware store. The bushing is more than likely to have a metric thread pitch. Take the part with you so the correct bushing can be obtained the first time. REMEMBER the anti-seize compound!
In the event the threads in the exhaust manifold are defective they might be replaced with new threads even with the manifold in place if there is enough working room in front of the threaded hole. A threaded insert can be installed. They are available in most pitches, and sizes both metric and standard. They are installable by one with reasonable mechanical skills and common tools.
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