Contour Enthusiasts Group Archives Forums General Troubleshooting 98 Contour O2 sensors

1st: How many O2 sensors on the V6? I have had the 2 lower replaced and 1 upper. Now the other needs changing. How bad of a job is it to replace the upper one next to the firewall?
2nd: What are pre-cats, I read another thread regarding these. How many of these are there?

98 Contour Sport V6 auto, 83k miles
TIA
Tim

Welcome onboard.

The oxygen sensor you mention is the most difficult to access of the four on the v6. Not impossible, but not the one to start DIY training.

The pre-cats are between the 2 sensors on each exhaust manifold. The upper sensors input to engine operation (important), the lower ones check performance of pre-cats (less important).

Welcome to CEG! The pre-cats are very close to the engine and help clean up emmisions when the car is first started and the main-cat is still cold. If you pull the coil pack, you should be able to get an O2 sensor socket and breaker bar on the upper sensor. Others have used a stubby wrench and pushed on it with pipe. You will probably end up sitting on top of the engine so you can reach down to position the tool, but it's not bad once you figure out how to get it loose. Use anti-sieze on the threads of the new sensor.

HI There.

My 95 Contour has only two o2 sensors, but I believe the one you are now asking about is common to both cars. I can tell you that it is by far the WORST DIY project I have yet done! My car is loaded with auto-tranny, and my goodness, I simply had one hell of a time getting to that sensor. Going at it from underneath was near impossible as well. My brother and I finally got it, but WOW.

Removing the coil pack is good, but there is a large and VERY STIFF wiring harness thingy with what appears to be a very high amp fuse attached to it that is a major BIGTIME PIA!

If I had a choice of replacing my oil pan gasket again or that #$%@#!! sensor, I'd really have to think about it!

You never know if you don't try though!

Good Luck

Jab