Hi Everyone,

Looking to fabricate new pipes and O2 sensor mounts on my OBD 1 3.9. Anyone know the thread size for this particular sensor? I mistakenly picked up M18 x 1.5 bungs off Amazon from researching other threads only to find out they are quite big.

O2 sensor thread size in question:


Thanks in advance!

 

M17 x 1.5mm as I recall, but take the sensor into a hardware store to check for sure. NTK might specify the thread size online.

I plugged two of the four holes with bolts when I swapped Y-pipes from the '96 to the '94, but that was a while ago.

 

Follow up with more details. Did some work today on the exhaust. The O2 sensors use a 17 mm wrench. The thread size is 12 mm x 1.25 mm pitch.