What the sludge?

[g-man]

Re-installing a rear main seal today. Used Poser's method of removing the oil pan and rear bearing cap. Must say it is THE WAY to do a rear main seal. The last one I put in about a month ago when I rebuilt the tcase and installed a new clutch. My friend and master mechanic tapped it in with a ball peen hammer. Looked great from the outside but it cut the inner lip of the seal (inside where you cant see it). Of course it leaked like a sieve.

While the oil pan was out I couldn't help but notice the sludge build up on the oil pick up screen. Holy cow. At 300k and this oil has been changed regularly over the last 10 years. I sprayed it out with brake clean and wire brushed it. Glad I pulled the oil pan off! Amazingly the rear crank bearing shows no wear.

 

[g-man]

Has anyone ever run some kerosene through their engine to remove sludge? What were the results? How much did you use?

 

[g-man]

If you look at the metal pieces of the oil pick up and bottoms of the pistons, rocker arms etc...everything is coated in the golden sticky sludge.

 

[KLF]

When you put the new oil in, substitute one quart with Marvel Mystery Oil. Run for about 500 miles, dump and repeat. Might take 2-3 flushes. I've done this a couple of times on older engines and it really helped.

 

[tmxmotorsports]

I did in a dodge Dakota it is still running but I don't think I would do that to my cruiser don't remember how much I used long story tho

Has anyone ever run some kerosene through their engine to remove sludge? What were the results? How much did you use?

 

[OSS]

Trying to remove sludge is a time bomb. It ends up getting dislodged and spread and travels in the oil passageways and blocks small openings to bearing journals and pretty much can wreak havoc on the whole engine. The words of the wise is (I'm quoting here) Don't try to remove sludge unless the whole assembly can be torn down and hot tanked- or something to those words.

That's easy enough to do for something like the rocker assembly or the inner surface of the pushrod cover, (which notoriously collects sludge due to crank case venting) but if the crankshaft and everything inside the oil pan is coated with tar- disturbing it could spell the end to your engine down the line.

All that tar-in-the-making coating the inside of the engine was caused by using crap oil (as far as sludge formation is concerned) and overly drawn out oil change intervals.

Just for comparison I'll include a picture of my oil pump. It's the original that came with the engine and is 30 years old. Has 300,000 miles on it. The film you see on the bottom of half the screen is just an oil film. Like a bubble wand. Zero sludge.

Why is it so clean?
The engine has run on synthetic oil since 1989.

 

[Prairie Swamp]

Let sleeping dogs lie. I was shocked at the crusties inside my 362k 3FE. No good can come from disturbing anything* unless you plan on the full monty as OSS said.

* I did hot tank the valve cover and give the oil pan a refresh - but these are removable independent pieces.

 

[Kleatus]

My thoughts - what’s not there can’t break up and clog anything up. Clean is good.

When I had my cylinder head off several years ago my engine was filthy. Disgusting. I cleaned it all up. Some of the same comments were made “don’t disturb the sludge”, “you’ll blow it up.” Well I’m happy to report that several years and ~40k miles later it’s still going strong. At the last valve adjustment the top end was still squeaky clean (now that it gets good oil that is regularly changed!).

If you are scraping and cleaning on the bottom end of the engine, if you miss something and some piece of junk comes loose and falls into the pan - it will be stopped by the screen or the oil filter, and will subsequently removed during the next oil change with no harm done. The same can’t be said for running aggressive (relative to oil) solvents in the oil, like ATF or kerosene or MMO (which is essentially a 70/30 mix of mineral oil and mineral spirits), etc. With that you do run the risk of crap coming loose after the filter and before a bearing. It’s a similar situation to dumping a bottle of Techron into the tank of a vehicle that hasn’t run in a long time. Best case you’ll need a few fuel filters. Worst case you will render the fuel pump and injectors worthless with all the crap you let loose all at once. I learned that one the hard way.

 

[g-man]

what do you think about spraying the bottom end with 2+2, and maybe use a nylon brush. It's goey not crusty if that lessons the chance of a solid piece floating around. I do see some black gobs under the pistons. Should I take off more bearing caps for inspection of the bearings and check to see the oil passages are clear?

 

[Prairie Swamp]

I mean are you having a problem other than it's dirty? Oil pressure issues? It bothers the hell out of me to button mine back up when it was all disgusting like that - but in some sort of weird Toyota F engine way it just works.

If you start pulling all the main caps off how far are you from a rebuild? It's your rig your call but I would (and did) stop right there and button her up.

 

[g-man]

Guess I'm just a bit paranoid. I do have a slight dry rubbing and vibration that I can't pinpoint. I've pulled the belts off and ran it cold and it's still there. It kinda goes away slightly but not completely with the clutch pedal depressed. I do have a new thrust bearing and it is greased. I have no loss or lack of power, My oil pressure stays steady. And the rear main bearing was not wiped. Should I check the rest? Pulling the main bearing caps off would be easy now with the pan off. But miles from a total rebuild right now ..including $$$ for the kit and head work.

 

[BGarcia88FJ62]

Just wipe and clean the crank, rods and even the underside of the pistons with some WD-40 and shop towels. You can take the screen off the oil pick-up and get it all cleaned up. You really shouldn't cause any issues by cleaning it up. Take off the valve cover and check out
the rockers for gunk as well same process wipe and clean shop vac any chunky stuff.
Fresh oil & Filter maybe a "Sea-Foam" Treatment. Put a couple hundred miles on it
several heat cycles, dump the oil. Fresh oil and filter and drive it, you should be just fine.
If this was already suggested in previous post my apologies I didn't read through all the responses.

 

[SteveH]

Has anyone ever run some kerosene through their engine to remove sludge? What were the results? How much did you use?

Kerosene is not oil and I would not use it. Maybe some MMO or a pint of ATF in 8 quarts of oil, but not more than that. As the others have said, time and regular oil changes will fix this without drastic measures.

 

[g-man]

I left it alone. Oil pan back on. RMS on, trans back in. Hopefully get more oil to the top end now. Haven't driven yet, still buttoning it up.