The short version is this. I have a 2011, 3500, crew dually that started leaking a small amount of oil about a year ago. It seems to be coming from somewhere up in the area behind the fan pulley.

Here's the longer, detailed version;
It never leaked a drop for about 5 years. Then, about a year ago (thinking back, maybe after the last oil change), it started dripping a bit of oil. There were oil drops all across the sway bar, a little on the pan, near the A/C pump, but also high on the front of the block (but not as high as the valve cover seam). Cleaned and searched as best as I could but could never see where it was coming from. The crank seal seemed fine, because although there was oil on the cover directly behind the balance, the back of the balancer was dry and in the backside recess, you could still see light rust. No oil.

So, about a month ago, I noticed the oil was high on the dipstick. I'm pretty sure that was my mistake & I had just overfilled at the last change. As I was reserching leak causes I found out about the CCV filter hidden on top. Pulled that and it was drowning in oil. Cleaned up area & replaced with new one. Drained the oil to proper level.

Still had leaking. Figured it must have blown out the seal somewhere around the timing cover. Pulled everything off (* more below), cleaned, installed a new crank seal while apart, & carefully reassembled. Went beautifully. However... still leaked. Maybe ever more. There doesn't appear to be any leakage around the timing cover and the seal is dry.

This is where it gets weird. Regarding the asterisk above; When I was removing items there wasn't any area of oil that seemed to be a source or appeared to be very "wet". Except for one. The fan pulley was shiny with oil, and if you reached in the backside with your finger, you could get a lot of fresh oil. I thought perhaps they ported oil into that bracket to lube the bearing and that was the cause. But after pulling it realized there was nothing anywhere there that seemed to be a viable source of oil. The front of the block wasn't wet. The plug in the face was clean (even a little rusty). Nothing seemed to be running down. So, I cleaned oil of everything.

After putting back together and driving about 25 minutes I saw it was still leaking oil. Looked every where and there were drizzles coming down the front of the timing cover. But once again, the fan pulley had a little oil on the mount casting, but the inside edge of the back of the pulley was wet with oil again. I can't seem to ffind anything in that area that could get it there.

Sorry for the length of this, but I'm hoping the details will be helpful and someone might say, "Yaaaaaa.... I know exactly what that is." Hoping that a lot! Cuz I'm baffled.
Thanks

 

Add some dye to your oil. Clean things up REALLY well, go for a SHORT drive, then hit it with the UV light. The dye should help you pinpoint where the oil is coming from.

Also, might not hurt to leave the engine at idle while you look around.... it might only be leaking while under pressure.

 

Thank you so much. Have a black light, so will need to get some die.
Okay, real embarrassed here. So I cleaned things up a bit and since I didn't have any die, thought I;d run a bit an see if I could see anything happening. Well, I did. But not where I wanted to. Turns our there are more than one places leaking.
There was also an oil leak at the oil filter. That was the one that seemed to be dripping the bulk of the oil on the frame & crossbar & sway & steering bars. (This is the embarrassing part) Evidently, when I did the last oil change, the rubber ring in the previous filter had pulled out of the filter and stayed stuck to the mount. It's so high up in that big hole where the filter is, that I didn't even see it. And when I was "braille cleaning" reaching up there with a rag, I didn't feel it was there. Put the new filter on top of it. It started blowing out. Such a no-brainer. In any case, took that off, cleaned, & installed new Mopar filter. No leaks on that side. Went back to the front & driver side. Cleaned with brake cleaner everywhere I could. Now going to test for leaks over there, without the distractions (and oil flying around) from the other leak. If I can't get it then, I'll get the die. Is it one type that can be used for oil leaks or water or ???. Or are there different types for the different fluids? Oh... does the oil need to be clean to use the die? Mine is about 2000 shy of a change, so pretty black.

 

You aren't the first to experience that with the oil filters. At the dealership, it was rather common, and we instructed out oil change guys to visually inspect EVERY time they changed a filter..... just checking the old filter, to see if the gasket was there should be adequate to the task. (assuming it didn't get doubled the last time the filter was changed. )

Parts store should be able to get you what you need. Just ask. They'll be happy to show you where it is.

 

Thanks, I don't feel quite as unobservant.
So far, that's stopped 90% of the oil issue. Just have to keep watching now. I have a bad feeling it might be coming from the seam between the face of the block and that 1" thick spacer-looking piece that the timing cover mounts on. I hope not. Cuz I really don't want to take all of this apart again.

 

Well, unfortunately I found the leak and it was the worst-case location. It IS the gasket between the block and the timing gear case.
I'm going to start a new thread or look for others regarding fixing that. The only up side (if there can be one), is that it is at the top edge, rather than the sides or bottom. Think I'm going to search for a work-around. Because I definitely don't want to tear my whole frickin truck apart and pull the cam shaft and everything, just to fix a stupid gasket leak. What I don't understand, is why they didn't make the cam shaft gear so you could remove it, so you didn't have to destroy all the good working part of the engine just to replace a gasket. That is soooooo stupid. Up till that, I was really impressed with the design & work-on-ability of this engine. But that?...Just really stupid.

 

I think there are two gaskets there? The cover gasket, and then another between the gear case, and block? Which one is leaking?

 

Ya, there are 2. The one under the cover, which I already did. Thought that would solve it but it didn't. Then there's the one behind the aluminum timing gear casing. THAT's the gasket from hell. And mine is... not good.