Seattle Scott

Hey Style12V, were those 02 Sensor pictures OK for your car? Locations correct?

muhammadc

Why there is another seemingly "capped" hole next to the sensors on the headers... also now I'm wondering the location of the O2 sensors on cars without OBD II and only two sensors. I think '96 was the first year for four sensors...

Seattle Scott

I have a vague recollection of test probes and alien abduction.

muhammadc

Confirms my suspicion.

Style12v

yup, not sure if they were exact same place, but I found the a-ok Thanks!

muhammadc

Two on the header pipes, two after the cats....

Seattle Scott

looks like the two 02 sensors are mounted in the back of the exhaust manifold. There are numerous references to "CO Tap Tube" and "Threaded Stud or Sealing Screw" also. The manual says they were deleted but I imagine the manual isn't "totally correct".

Thanks for reminding me I have four 02 sensors. Do they all have to be changed at once?

muhammadc

My mechanic told me that they're in the same place as the first two on our cars... I'll have to check next time I see my 100CS.

Supposedly Bosch lists a 100,000 mile replacement interval for the O2 sensors. But it seems like most people have problems with the O2 sensor codes before then... but the problem in my eyes is that it isn't always the O2 sensors that are bad. It can be anything from a fuel line or fuel filter to a plugged cat or problem with the exhaust. I've heard of people replacing the O2 sensors after they get the O2 sensor codes, then shortly after the same codes come up. Also, I've heard of people not replacing them and correcting something else, and the codes going away. I guess it depends on how the car is performing. Sometimes the car can be running perfectly with the O2 codes. other times the behavior of the car will be different. I think based on that I'd decide if I was going to replace the O2 sensors or not.

Not sure if we *have* to do all 4 at once, or not... maybe "they" can be easy on us and only require them to be replaced in pairs?