DIY O2 replacement

[Paul T. Casey]

Over the past 6 months or so, I've been getting a check engine light. I've had it checked, don't remember the exact codes, but it was always for the 2 after cat and right side before cat O2 sensors over voltage. After 3 or 4 times, it occured to me it always happened either after a carwash when I did the underside wash, or in wet weather. Last weekend, during the rain, it happened again. I purchased 4 new sensors (at store cost) and my son and I decided to replace them. What follows is what we consider to be the easiest, most time efficient way to do the job. We had access to a lift, but it should be fairly easy with th car on jackstands. We obtained an O2 sensor socket, but it seemed pretty much useless. Here are the required tools for the job. 1 4lb hammer, 1 7/8'" open end wrench, 1 pair of dykes (no, not that kind).

[Paul T. Casey]

Step 2, clip the wire ties, unplug the sensor, place wrench on sensor, and gentle tap the wrench with the hammer to loosen it. With a real heavy hammer, it doesn't take much to loosen the sensor. The sensor socket however failed to properly grip the sensor.

[Paul T. Casey]

Not surprisingly, the offending sensors showed damage to the wires. IMHO, the factory tubing over the wires is too weak to afford proper protection against rubbing. There were exposed wires (the metal part which carries the electrons to the computer) which when wet caused the check engine light.

[Paul T. Casey]

The new sensors had the same type of tubing on the wires. This tubing was also shorter than the wires on both the new, and the original sensors.

[Paul T. Casey]

To prevent this sort of chafing damage, I purchased and installed some 1/2 inch split loom conduit. I cut the conduit to the length of the wires, installed it over the wires, then secured it in place with electrical tape. I used blue tape to show how I wrapped it, but I don't think the color really matters.

[metroplex]

Let me guess: You bought Bosch O2 sensors? I bought them and they weren't the correct sensors for the front. Bosch's O2s are fine for the rear sensors (catalyst efficiency monitor) but take too long to switch for use as the primary O2 sensors. Stick with Motorcraft.

I used my own wire loom over the new Motorcraft sensor wiring for extra abrasion protection.

[Paul T. Casey]

Next, I removed the factory installed anti-seize compound from the threads, and applied the Permatex Copper antiseize in it's place. I seem to have had better luck with this stuff, and may be able to delete the hammer next time I replace the sensors.

[Paul T. Casey]

Sensors were re-installed, the protected wires were tied in place.

[Paul T. Casey]

The only tough one is the left side header side sensor. It's just a little tight, but really posed no problems.

[Paul T. Casey]

About an hour and a half later, including supper and cool down time, my mechanic was looking for more to do.

[Paul T. Casey]

In case you were wondering about step one, here it is. My mechanic insturcting me where to watch from, and me complying.

[O's Fan Rich]

In case you were wondering about step one, here it is. My mechanic insturcting me where to watch from, and me complying.
:beer:
What? No beverage in the waiting area?

[LVMarauder]

Nice write up. You get an A.

[metroplex]

Next, I removed the factory installed anti-seize compound from the threads, and applied the Permatex Copper antiseize in it's place. I seem to have had better luck with this stuff, and may be able to delete the hammer next time I replace the sensors.

The fluting definitely looks like the Bosch sensors. Are you monitoring your primary O2 voltage sweeps from startup by any chance? It took about 5 min for the Bosch sensors to start switching, while OEM took less than 30 seconds. Ideally the primary O2 sensors should start to switch when your PCM switches into closed loop (under 1 min from startup).

Been there, done that. Stick with OEM/Motorcraft O2 sensors.

[Hotrauder]

Paul, LV nice info and great pics. thanks. this is now or down the road for all of us at some point. Dennis

[O's Fan Rich]

When I did the X pipe, I carefully applied anti-seize before reinstallation.
Hopefully when my turn comes around, I can ease them out.
I got one of those O2 sensor sockets you can get ahold of with an open end.

[fastblackmerc]

A couple of things:

If you have to replace an O2 sensor it helps to have the exhust system hot, the pipes expand when hot and it's easier to get the sensors loose. Just be careful and not burn yourself. I also use a socket specialy designed to remove them.

When using anti seize on the sensor(s) do not get any on the tip, just apply it sparingly to the threads.

[metroplex]

Watch out for the cheap special O2 sensor sockets designed for heated O2 sensors. They are cast and can crack with enough force.

[jimlam56]

In case you were wondering about step one, here it is. My mechanic insturcting me where to watch from, and me complying.

I've got a mechanic/son like that too. Stay out of the way Dad, and I'll take care of it...:rolleyes:
I'm going to have to relearn everything once he flies the coop...:alone:

[Paul T. Casey]

We had a supposedly "good" O2 sensor socket, it didn't work. With the 4 lb. hammer, you just lightly tap the end of the wrench and they loosen right up. I'll also check if the Bosch sensors give me any trouble.