3.6L Oxygen Sensors

[CarbonSteel]

Spent a bit of time with the parts guy at Castle Rock Jeep to understand the 3.6L oxygen sensor "array" on the 3.6L as there are 4 of them.

As it turns out, sensors 1, 2, 6 as circled in green in the image are the exact same and is part number 68224424AA. Sensor #6 is the typical one that fails due to an oil leak on the passenger side PCV.

Sensor #5 as circled in red in the image is unique and is part number 68291423AB.

The only difference between sensors 1, 2, and 6 versus sensor 5 is that #5 has a much longer wiring harness.

Hope this helps someone!

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[speedymart]

The only difference is the length of the connector wiring. Also, #6 is the right side downstream which is the one that has the oil leak issue. The one you circled is the upstream which is up and away from the valve cover and doesn't have the same issue.

 

[CarbonSteel]

The only difference is the length of the connector wiring. Also, #6 is the right side downstream which is the one that has the oil leak issue. The one you circled is the upstream which is up and away from the valve cover and doesn't have the same issue.

I thought that too until I checked. The one that is coated in oil on my JLUR is at the top. The bottom one is much farther down and is close to the transmission.

 

[speedymart]

I thought that too until I checked. The one that is coated in oil on my JLUR is at the top. The bottom one is much farther down and is close to the transmission.

Yeah, the valve cover leaks at the back right corner which leaks to the oxygen sensor that's directly below the corner. It's like a perfect angle to contaminate it. I've probably replaced over 100 of them at this point. If your upper oxygen sensor is covered in oil that's super weird

 

[CarbonSteel]

Yeah, the valve cover leaks at the back right corner which leaks to the oxygen sensor that's directly below the corner. It's like a perfect angle to contaminate it. I've probably replaced over 100 of them at this point. If your upper oxygen sensor is covered in oil that's super weird

It is caused by the catch can hose cracking and leaking. I have both right side sensors ordered because I will probably change both and be done with it.

 

[speedymart]

It is caused by the catch can hose cracking and leaking. I have both right side sensors ordered because I will probably change both and be done with it.

Ah, that makes sense! Never thought using a catch can on a 3.6

 

[CarbonSteel]

Ah, that makes sense! Never thought using a catch can on a 3.6

It catches about 200ml in 5K miles, but UPR's hose connector design/material is crap and it becomes brittle and cracks. Then you have the PCV spewing oil that makes its way to areas where it should not. UPR sent me a new hose at no cost, but I removed the can and likely won't reinstall.

 

[CarbonSteel]

I changed both of the passenger side sensors last night and it was somewhat of a PITA. In the end, I pulled the fender to gain enough access. The bottom sensor is best tackled from underneath and you will need a "cheater" pipe for your ratchet, unless you have a really long handled 3/8" ratchet or breaker bar that can fit in the space. This crow foot socket from Amazon is a must have - https://www.amazon.com/dp/B00GMN4D1Q

The new sensors came with some anti-seize on them so that was a nice addition. Hopefully, these are the ones that are defective, though neither of them had an oil to speak of on them. I do have a valve cover leak so I'll probably wrap that job together with my oil cooler project which I will change the sparkplugs while I am that deep in it.

 

[speedymart]

I changed both of the passenger side sensors last night and it was somewhat of a PITA. In the end, I pulled the fender to gain enough access. The bottom sensor is best tackled from underneath and you will need a "cheater" pipe for your ratchet, unless you have a really long handled 3/8" ratchet or breaker bar that can fit in the space. This crow foot socket from Amazon is a must have - https://www.amazon.com/dp/B00GMN4D1Q

The new sensors came with some anti-seize on them so that was a nice addition. Hopefully, these are the ones that are defective, though neither of them had an oil to speak of on them. I do have a valve cover leak so I'll probably wrap that job together with my oil cooler project which I will change the sparkplugs while I am that deep in it.

If you replace them through the fender liner it becomes a 5 minute job. Definitely the way you should do it going forward. If the valve cover is leaking simply tighten the rear most directly above the oxygen sensor and you'll find it's not even remotely tight from the factory

 

[CarbonSteel]

If you replace them through the fender liner it becomes a 5 minute job. Definitely the way you should do it going forward. If the valve cover is leaking simply tighten the rear most directly above the oxygen sensor and you'll find it's not even remotely tight from the factory

I was not able to get enough access to do it by peeling the liner and pulling the fender is simple (after having done it a few times). You lose some clips, but peeling the liner means drilling rivets so six of one and half a dozen of the other.

I plan to check tightness, though most of them are "double studs" so you may have to remove what's on top to be able to tighten the bottom.

Still amazed they shoehorned a V8 under that hood...

 

[speedymart]

I was not able to get enough access to do it by peeling the liner and pulling the fender is simple (after having done it a few times). You lose some clips, but peeling the liner means drilling rivets so six of one and half a dozen of the other.

I plan to check tightness, though most of them are "double studs" so you may have to remove what's on top to be able to tighten the bottom.

Still amazed they shoehorned a V8 under that hood...

You can actually just pop the liner off the back of the rivets. The liner doesn't actually get attached to the back side of those rivets, just has holes to go around them. They're just locator holes, the bottom push pins are what really hold that side together. When you're putting it back on you just slot it back over the backside of the rivets and you're good to go. Only thing you may break is one of the two bottom push pins as they're brittle, but also easily replaced.

 

[CarbonSteel]

You can actually just pop the liner off the back of the rivets. The liner doesn't actually get attached to the back side of those rivets, just has holes to go around them. They're just locator holes, the bottom push pins are what really hold that side together. When you're putting it back on you just slot it back over the backside of the rivets and you're good to go. Only thing you may break is one of the two bottom push pins as they're brittle, but also easily replaced.

Your setup is different than mine. My liner has holes in it and not slots, the rivets expand on the backside of the liner and in addition, I have the XR fender extensions so I have even more holes than a standard fender.

I have pulled both sides at different times and depending on what I am doing, I drill rivets and pull the fender liner back or I completely remove the fender. Once you do it a time or two, it is straightforward work.

 

[Ozionjon]

This is great info. im getting the following codes:

p0171 Fuel trim too Lean Bank 1
p0133 O2 Sensor Circuit Slow Response
p0300 Random multiple cylinder misfire
p2096 Post Catalyst Fuel Trim System Too Lean Bank 1

Could a bad 02 Sensor be my problem?

 

[CarbonSteel]

Yep. Check and see if the PCV on the rear of the passenger side valve cover is leaking oil onto the sensor.

 

[Ozionjon]

Will do. thanks for the info!

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