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Bad Sludge, what now..? (Solution!)

1232 Views 3 Replies 3 Participants Last post by  bingwrite
Solution write-up on reply #4. Use at own risk.
While theoretically safe, unforeseen circumstances can cause damages to other motors.

First post here, 98’ Dakota 4x4, 5.2 Magnum and 5 Speed.
Got a real brain racking situation here…

Pulled the intake off my Dakota to fix the plenum leak and uncovered what seems to be a nightmare.
Automotive tire Tread Wood Font Auto part

Yeah, yikes, I know. After scratching our heads and a little more than a couple beers, a buddy and I started digging up the sludge in the valley and shop-vac’ing it out. Not the best idea. After scrapping and scrubbing were left with a sort of “oily-ATF soup”. Now we’re wondering what should be the next step.

Option 1: Fill with 2/3 diesel and 1/3 ATF, soaked for a day or two and then drain. Part B of that plan is hope and pray it doesn’t eat the oil pump.

Option 2: Same as before but spin the oil pump up with a drill, drop the front diff, oil pan, and oil pump, clean the screen and slap it back together. Figure it’d cost me more in beers. Problem is, I’m lazy lol.

Option 3: Yank the engine. Once again, I’m lazy, but I like this truck so I’m considering it.

You all have any brighter ideas than a couple of alcoholic mechanics? Kinda hit a roadblock here.
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Clean the valley the best you can, soak up the “oily-ATF soup” with rags. Put everything back together, check your PVC system and thermostat. Do a couple of 1000 mile oil and filter changes and you'll be OK.
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.

this is sludge

pull your valve covers off and see if something like this is layin on the heads, if so youll be better off pullin the motor out, this is sort of a common issue.
Link to forum:

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
Here’s the scienc-y part. Both previous guys I mentioned, recommended an mix of 80 parts oil to 20 parts kerosene, “flush mixture”. If you’re doing this process first hand you probably already noticed how the kerosene breaks down the solid oil sludge into a sort of fine oily powder. Kerosene is good at this and I was concerned at first, of it clogging the pickup tube but after some deliberation and more beer, I’m pretty sure ~50 PSI of oil pressure will break down the particles, further returning it to oil.

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)
Repeat until hearts desire. 3 flushes recommended but 1000 mile changes suffice. You may notice increased valve train noise and lower oil pressure during this process. This is to be expected as kerosene is thin. At the time of this process I have chosen 2.5 gal Rotella T4 synthetic blend 15w-40 as a flusher. Will be switching to full synthetic in 3000 miles.

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.
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