'98 Dakota 5.2L 4x4 automatic, 160k miles. Did the valve seals recently and saw sludge, didn't seem like a lot compared to some pictures I've seen but there were small chunks of gunk on the springs and other places. I'm thinking there is probably a fair amount of that gunk in my oil pan and it could explain the oil pressure flakiness that I see after the engine warms up.

I know what the ideal solution would be, and I've done a lot of work on the truck like plenum gasket, timing chain and heater core, but dropping the oil pan looks like a giant PITA on the 4x4 so looking for something simple to try first. I see some people recommend putting kerosene in and running the engine to flush it but I don't feel comfortable doing that.

Saw someone else mention that you could drain the oil, put the plug back in, put in 2 (or more?) quarts of kerosene down the oil dipstick tube enough to soak the oil pump screen, let it sit overnight, then drain that out and that should help clean out some of that gunk as well as cleaning the pickup screen. I was thinking of pouring a quart of two of oil in after that, let it sit and then drain that to flush out any leftover kerosene. Then of course new oil filter and oil.

Has anyone ever tried something like that, and was it effective? Seems tame enough since it's not circulating through the engine. Also I'm not sure how much kerosene to add to sufficiently cover the oil pickup screen and not be in danger of affecting anything else.

Thanks for any insights.

 

I have seen some folks use diesel in the oil pan, run the engine for a bit, and then change it out.... but, I have also seen folks waste rod/main bearings that way. Another problem with doing that is it can be TOO effective, and ALL that crap ends up in the oil pan, clogging the pickup, and also smoking bearings. Better plan might be to just use rotella oil, (for diesel engines) of the correct weight, and just change the oil more often for a while. The rotella oil has more detergents in it, than typical automotive oil, so, it cleans the junk out SLOWLY, and it accumulates in the filter. Its a longer process, but, MUCH safer for your engine.

 

I had no intention of running the engine with the kerosene in it at all. This plan is to pour kerosene only into the dipstick tube so it goes right to the oil pan and let it sit to dissolve the gunk on the pickup and bottom of oil pan so it flows more easily, then drain it out. Maybe even do that a few times. Then remove any kerosene residue with some motor oil (still not running the engine), drain that, then replace filter and put new oil in.

 

Around 1/2 quart of Marvel Mystery Oil in the pan for a few weeks will slowly dissolve the sludge its a slow process but safer.

You drive and it dissolves the crud NOT FAST SLOW.

 

I assume this was mostly run on conventional? Run synthetic oil exclusively.

 

Have seen this as well. People run gunk cleaner (of a given choice) in a high mileage engine, and the following results:
1. The gunk falls down to the oil pan pickup, blocking it off
2. The gunk that was helping seal the piston rings and valve seals is now gone, resulting in oil entering the combustion chamber

Kerosene, Marvel Mystery Oil, and Seafoam are all methods to degunk. Choose wisely.

 

Wasn't going to pour it in at the valve cover. Was going to pour it in via the oil dipstick tube so that it goes directly to the oil pan, bypassing the rest of the engine.
Was not going to run the engine at all. Just going to let it sit there a while, probably overnight, then drain it out.
The hypothesis is to dissolve the gunk at bottom of the oil pan, and to put enough in to dissolve any gunk on the oil pump pickup screen.

 

Need a way to agitate it to make it truly effective.......

 

Most of the heavy sludge sits in the sump, so take the drain plug out and the thinned out gunk should flow out. Best method would be to pull the intake manifold and dump the thinner down the timing cover, draining front to back.

 

That would be easier than pulling the oil pan.