Camshaft Position Sensor Oil Failure

M

mphilleo

Member
About a year ago, I did a little overhaul on my 2012 JKU. New plugs, PCV valve, and valve cover gaskets, among other things. I followed all installation and torque specs to the "T" but recently noticed some oil seepage. It appears to be coming from my passenger side camshaft position sensor.

It was wicking oil up to the point that the wiring harness attached to it was wet and it was seeping down the side of the valve cover. To verify it wasn't the seal on the retaining bolt or valve cover seal (which was replaced), I cleaned it off a couple hundred miles ago. After checking it, it was moist with oil again.

It appears that the sensor must have an internal failure allowing oil to pull through the sensor, into the base, and into the female end, allowing oil into the male plug and up the wiring. This is the only explainable source of oil and I think it's definitely possible. Is this something anyone else has heard of or experienced? At this point, I'm probably going to just replace the sensor, even though it hasn't thrown a code for it yet.

Here's some pictures:

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Looks to me like the sensor itself is leaking through the plastic. Hopefully it doesn't get into the harness. Mercedes has a problem with this and the fluid can travel through the entire harness and damage modules. I can't say that I've seen that happen on Jeeps.
 
mphilleo said:
About a year ago, I did a little overhaul on my 2012 JKU. New plugs, PCV valve, and valve cover gaskets, among other things. I followed all installation and torque specs to the "T" but recently noticed some oil seepage. It appears to be coming from my passenger side camshaft position sensor.

It was wicking oil up to the point that the wiring harness attached to it was wet and it was seeping down the side of the valve cover. To verify it wasn't the seal on the retaining bolt or valve cover seal (which was replaced), I cleaned it off a couple hundred miles ago. After checking it, it was moist with oil again.

It appears that the sensor must have an internal failure allowing oil to pull through the sensor, into the base, and into the female end, allowing oil into the male plug and up the wiring. This is the only explainable source of oil and I think it's definitely possible. Is this something anyone else has heard of or experienced? At this point, I'm probably going to just replace the sensor, even though it hasn't thrown a code for it yet.

Here's some pictures:

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Jesus. I noticed some oil on mine on the passenger side too. Looked like it was only around the base of the sensor tho. I cleaned it off and forgot about it. Driver side was dry….Thanks for the reminder. I might swap both for piece of mind..
 
Cousin Clyde said:
Jesus. I noticed some oil on mine on the passenger side too. Looked like it was only around the base of the sensor tho. I cleaned it off and forgot about it. Driver side was dry….Thanks for the reminder. I might swap both for piece of mind..
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No problem. I guess that means this isn't an unheard of failure mode for these sensors. As best I can tell, looking at the valve cover through the gaps, the driver side isn't seeping yet. I'd do both, but I really don't feel like taking off the intake manifold again! 😅

I do think that this was already happening when I first did the job. That's why the seepage on the passenger side valve cover was so heavy. There were broken tabs and witness marks showing someone was over there previously (I think to replace the oil cooler or some other service).
 
WJCO said:
Looks to me like the sensor itself is leaking through the plastic. Hopefully it doesn't get into the harness. Mercedes has a problem with this and the fluid can travel through the entire harness and damage modules. I can't say that I've seen that happen on Jeeps.
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This^^ have seen it on MB and a few other German brands but never on a mopar product. Replace the sensor and clean out the connector with brake clean the best you can
 
cozdude said:
This^^ have seen it on MB and a few other German brands but never on a mopar product. Replace the sensor and clean out the connector with brake clean the best you can
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Yeah, I've heard about this on the NAG1 transmission wire harness adapter. ATF traveling up the harness into the cabin and into the computer. Bad times. I have a replacement part and will be swapping it in. Kind of a weird failure mode, but I guess it's possible.
 
For anyone still curious, I though I'd provide a quick update. After replacing the sensor a couple days ago, I didn't find any new leaks or weeping on the harness. I'd say so far, so good. What an odd failure. After inspecting the old unit, I couldn't find any immediately obvious causes for the leak.
 
mphilleo said:
For anyone still curious, I though I'd provide a quick update. After replacing the sensor a couple days ago, I didn't find any new leaks or weeping on the harness. I'd say so far, so good. What an odd failure. After inspecting the old unit, I couldn't find any immediately obvious causes for the leak.
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Good to hear.

I’m gonna swap the passenger one, but the driver side one is going in the fuckitbucket. It was dry when I put the intake manifold back on…let me know next time your in there if you notice oil on yours and I’ll check mine if you see any😆
 
Cousin Clyde said:
@mphilleo, it really is odd tho, that both our passenger sides were clearly bad and the driver side was dry…coincidence maybe…
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It's either got to be a coincidence or a design flaw/engineering quirk. I certainly hope my driver side sensor is good - I don't want to go through the process to access it, although I've gotten pretty good at it. 😅 The big question is whether I put a Mopar one on or a parts store brand. On the passenger side it was no big deal going cheaper because it's so easy. I'll have to keep an eye on the other side.
 
@Cousin Clyde that's probably for the best. It was a bit of a pain to fully clean the electrical connector and wire harness. I'm honestly not sure if the retaining bolt or o-ring can cause a leak like I experienced. It doesn't appear like the design seals from those things, but who knows? 🫠
 
Cousin Clyde said:
Yea I’m not sure either…but any time I can throw 35 dollars and 20 minutes at my jeep and have less oil leaking out, I’ll do it.

What did you torque that T30 to? Just a 1” breaker bar and a 4 foot 2” pipe?
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I used my 1/4" torque wrench set to 80 in lb with some extensions for clearance. No problems yet.
 
Crap! Now mine is doing this too on the drivers side! Frustrating that I just replaced the sensor two years ago and with a Mopar part! The top and sides of the sensor are bone dry, but the wires for the connector are coated in oil.
 
ScottofKSU said:
Crap! Now mine is doing this too on the drivers side! Frustrating that I just replaced the sensor two years ago and with a Mopar part! The top and sides of the sensor are bone dry, but the wires for the connector are coated in oil.
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In a way, it's comforting to know that I'm not the only one experiencing this failure mode. I didn't disassemble my old one, so I can't really say but obviously there's a bad seal where the wires terminate at the plug and the oil contacts, allowing permeation into the wire harness. It's funny though, I didn't hear more about this until my OP.
 
Makes me wonder if Mopar had a bad batch of sensors... I will take a picture of the markings on mine and post it here once I get it out this weekend. That way, if anyone else experiences this, maybe we can identify - pretty much just for academic purposes - a common lot from which these sensors are coming.
 
Hey guys, sorry to bump a few months old thread, but I think my Jeep is experiencing this. It's a 2015 with 60k. Could this leak enough to drip oil down to my O2 sensor? Something is dripping on my driver's side and hitting my sensor and causing a code. This is the highest item in the engine that appears to be wet. I have also heard it can be the oil filter housing (still have the original plastic one), but the passenger side of the engine seems dry.

Here's a view up from the O2 sensor:
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And I believe this is the camshaft sensor? Definitely wet around it, but hard to get the camera in there.
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