Anybody have any wonderful ideas on how to best get rid of engine sludge? I am doing a cam swap and the sludge buildup is more than I thought was good. I would like to reduce it with multiple oil changes or a flush if possible. Anyone have any brainy ideas?

 

That is a very good question & I'll be interested to read what some have to say.

I guess an important factor to ask is, how the sludge got in the engine to begin with & as it was building up, what slite damages has it done to the engines workings on the inside.

Every engine I've ever seen that had sludge build up, was in an old persons car or truck, that only puttered here & there getting somewhere & the engine oil never got hot enough for the chemicals in the oil to do its job of cleaning the insides.

Your problem now, would be, if you add a cleaning product in with the oil, if it cleans the insides to quickly, it could stop up the pick up tube to the oil pump & starve the engine causing even more damage.

Theres probably a bunch of engine cleaning products on the market, I've never used any, but have added a qt of Marvel Mistery to the oil change ever once in a while to clean the insides.
Neil

 

I do have some Marvel Mystery Oil I can try. I did read on another post in here that some of the engine flushes are like taking sandpaper to your bearings. So I dont think I will try those unless someone knows better information on that.

 

If you have time, a good oil change or two with some good quality oil will slowly remove the sludge and dirt.

You could also try Marvel, or other Engine Cleaners or even Kerosene or Automatic Fluid.

The quick cleaners like those mentioned above have some risks. Depending on what is in the sludge, the quick cleaners will release the sludge fairly quick. If there is grit or dirt in the sludge it will circulate in the engine and get into places you don't want it. It could also clog the filter which means that pure sludge will then be running thru your engine.

If the sludge is just normal fuel and water contamination or thickened old oil, you should be fine whichever method you use.

I have read that the kerosene or ATF method works well but you must leave the engine at idle with no load on it and then drain it after say half an hour of running. But there are risks as mentioned.

Of course in all cases use a new filter when you are done and between changes if you are doing mulitple changes.

Good Luck,

Jim Henderson

 

Hello, down here In Australia a few chaps I know who own a wrecking yard have used Diesel a few times to remove sludge from there V8's, I once did it to a 351ci with no problems what so-ever, 1. Drain old oil, replace drain bolt, 2. Fill with 4 to 5 litres of diesel, 3. Start engine up and let idle for a couple of minutes or go for a slow drive around the block, 4. Drain diesel and refill with a cheap priced oil & change oil filter, after that next oil change put a top grade oil in engine, it worked for me..

 

I have wondered how the sludge got there too. I have worked on a lot of other peoples vehicles with a lot of sludge. I have run some of my engines now for over 20 years and no sludge. I always change oil at 2000 miles and like to open up the carbs now and then. Have heard of the diesel and Marvel oil trick. Not sure how good it works. I know there are some motor flush aditives you can buy that you put in before the oil change that is suppose to clean out that stuff. Don't know how good it works though.

 

Sludge, I'll give you my decription of what it is.
Blowby seeping past the rings carrying unburnt gas & carbon with it. Moisture, from a hot engine turning cold the moisture acumulating inside the engine & then trapping the blowby products within the build up of moisture laydened oil. Then you have the driver, just making short trips & the brand of oil being used, never gets hot enough for the chemicals in the oil to do its job of removing all that built up junk & it being washed to the filter.
Once you start getting a build up & if the oil dont get hot enough to cause the chemicals in the oil to wash it away, it just keeps piling up untill it damages something.
Short trips are the worlds worst at causing sludge build up. You keep pilling up cold oil & soon or later thats what you end up with, sludge.

To remove it, you first need to know what will desolve it.
Just like as with paint, its thick in the bucket & have to add in a thinning agent that will mix with it in order to make it thin enough to use.
Sludge, being the build up it is & it being mostly oil, something like kerosene, diesel fuel would be a thinning agent. Gas would even be a thinner, but would work to fast probably.
Something like acetone or toulene mixxed with oil would be a thinner of the sludge, but would work way to fast & no telling what it would damage on the engines insides. Things like the valve seals, crank seals or anything rubber that the harsh solvent would touch would be bad.

I've always wondered, what it would be like on a engine with alot of build up, if you heated the engine up fully, dump in a gallon of acetone & then filled the engine completey with kerosene, all the way up to the PCV valve in the valve cover & just let it sit.
If you had some way the heat the engine as it was sitting probably would work better & do this like a day or over night.
If it could be done with out damaging the engine on the inside, I bet if would clean it up.
Might would need to do it several time before running the engine though & change the oil after about 100 miles & filter.
Neil

 

Dont think you should run her on diesel to clean her out. Diesel does not have the viscosity to sustain the required pressure to keep the bearings and journals from meeting on unfrendly terms (those are "pressure dam" bearings!") As far as the acetone, I bet that would work clean her out, but it may also clean the gaskets right out too!! If it was my engine to experiment with, I would run some Marvels in her for the next 2 or 3 oil changes using quality oil with an interval of 2000 miles. Oh and those flushes scare the poop out of me!!! Good luck!!!!

 

Full synthetic oil changes will clean out an engine pretty well. I have also used Seafoam, and the ATF added before an oil change. I think the sythetic oil cleaned the best/quickest.

 

I second the full synthetic oil route for cleaning out the sludge.
I purchased a 94 Camry about 6 years ago that the owner only changed the oil every 7500mi and it looked like it inside the valve cover, it was not pretty. Anyhow I changed the oil when I got it home to synthetic. 3000mi. later I change the oil again but this time I cut open the old oil filter and could not believe how much crap was being disolved out of the engine. Been using synthetic every since and oil filters and inside the valve cover looks good now.
Shell Rotella 5-40 syn. at Wally world is about the best price in the 5qt. jug.

 

The only thing I have heard negative about full synthetic is that if you put it in an older engine it can start to leak. I would hate to start leaks where it aint leaking yet if I can do something else. Mayeb I will go the seafoam and regular oil changes for a bit and see how that goes. For one thing I already have the seafoam and a couple cases of oil. Thanks everyone for your input, all very interesting.

 

Synthetic oil molecules can get where conventional oil can't, therefore as it cleans the engine it may pass through a seal or gasket that conventional oil couldn't get through. Usually you don't get any new leaks, the ones you have may get a little worse.