Yep, came to that conclusion. Too much work to pull the motor. Good eye on checking the PCV, they were completely clogged up. Thermostat was old but still worked okay.
I’m not sure if this is ”sticky thread“ worthy but after a ton of lurking thru old forums, it’s seems that these Magnum engines have had a long history with sludge build-up. From poor PCV design, to Penzoil pushing their terrible line of oil when these trucks were being sold out of dealerships, it’s really been a headache for 2nd and 3rd owners.
I dug up two forums in particular and will quote/link them here. They’re from like 2005 and the pictures are still up to my amazement.
Link to forum:

how to remove oil pan on 5.2 durango
I am trying to remove my oil pan on a 5.2 V8 durango. Do i have to lift the engine, remove the axel, or any thing of that nature. Or is there enough room that i can just remove it. Im looking too see if the filter is sludged because i hear lower engine knocking and i feel that the pressure might...
So in conclusion, the users @addicted2blue00 and @TurboBlew have two fairly decent “write-ups” on their process of removing sludge. (Will edit and link)
This is my amalgamation of their processes
- Suck up as much as you can with Shop-Vac and plastic scraper. Try not to drop any in the cam bores
- Soak stubborn sludge with kerosene for a couple hours
- Get it clean. Like clean, clean. Repeat kerosene soak if need be.
- Be sure to clean top of lifters so the lifter keepers will return to place.
- Clean intake manifold with kerosene or whatever. Just get it clean and remember to degrease gasket surface with acetone.
- Replace Gaskets and Re-Install Top End
- Flush Engine oil and replace w/ cheap filter
They also recommended to remove the oil pressure sensor (back of block, next to distributor) and blow some compresses air down the hole to further break up any chunks in the oil pump pickup screen. This is a very good idea if you think of it before throwing the keg back on.
The steps for this process is simple.
- Add flush mixture
- Start engine
- DO NOT PUT IN DRIVE OR REVERSE. The engine cannot be under load
- Let heat soak for ~10 mins
- Drain oil
- Replace filter (optional but best results)
Hope this helps all who view. Will take pictures of process and detail explanation further upon request. Also will be updating as truck did have intermittent oil pressure loss but I think it was a sender.