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Discussion Starter · #1 · (Edited)
A couple of months ago I promised to describe a procedure which chemically cleans engine to pretty much factory condition. It is a very effective process, and it completely frees oil rings, cleans oil drainage holes on pistons, completely disolvess all gunk/lacquer/deposits inside your engine, eliminates issues with hydraulic lifters caused by dirty pistons, etc. Also, another procedure stage cleans combustion chambers, removing all carbon from piston surfaces and cleans and frees compression rings.

The process wasn't invented by me. It is well known and widely used in Russia. I just reviewed it and made some adjustments based on my experience and understanding. The principle at work is also not new: adding a compound to engine oil to clean engine internals, and pouring a liquid into cylinders to clean combustion chambers.

I will try to describe the process as detailed as possible, and will answer any related questions. Before continuing, I must stress that anyone who does this procedure does it on his own risk. Please read instructions thoroughly and ask questions if anything is unclear before you decide to start. Do not neglect any precautions I mention.

The main reason to do this procedure is to eliminate oil consumption caused by stuck piston oil rings and clogged oil drainage on rings and pistons. There are similar products such as Liqui Moly, BG line, Seafoam, etc. I will not discuss them now. I just have to stress, that both LM and BG are very good for preventive treatment. These can help some, but have limited cleaning ability. I would suggest to try BG EPR liquid first, and if you are not satisfied with the results, then try the method described below.

The name of the compound is DMSO (dimethyl sulfoxide). It is a very interesting substance with several unique properties. You can Google it for more information. What makes the following process different from others? The ability to dissolve stubborn deposits; its power to do so compared to all other products is like a tactical nuke charge vs firecrackers.



Important DMSO features:
  1. It is a clear liquid, odorless until heated up.
  2. It is a very powerful solvent. But, unlike most chemicals used for such a purpose, it is far less toxic. Note that it can be unsafe, and I will get to that.
  3. It is very powerful paint stripper.
  4. It dissolves many plastics, although safe for the ABS used in our engines.
  5. It softens most rubbers, which has to be taken into consideration. I will come back to that later.
  6. It is pretty inactive at room temperature, but gets more aggressive at temperature increases. At 60 C and above it does its magic.
  7. It can penetrate through skin membranes. It is even being used in medicine as a transport to deliver certain elements through the skin, significantly increasing effectiveness of topical treatment. That is why it can be bought in pharmacies in Russia (it is really cheap, like few dollars per liter). That DMSO feature requires certain precautions, and I cannot stress enough the importance of following them exactly.
As stated, it is a clear odorless liquid, and if it gets on your skin it doesn't cause any immediate irritation or itching, so it might go unnoticed. Anything mixed with DMSO, be it engine oil, dirty water, etc., will pass right through skin, so you can imagine the consequences. It doesn't burn skin, nor make it red or itchy. But if left unattended, soon your skin looks like you soaked your fingers for an hour in hot bathtub. Gloves and goggles are compulsory. Be ready to change them. I use nitryl ones and they show no signs of damage. If you get any amount of liquid on your skin, wash it with water immediately. Vapors are flammable, so no open fire is to be used. Hot DMSO vapors smell like a garlic, so perform all work in a well ventilated area.

Now to the actual process. You will need 400 ml of 99% DMSO liquid for every 7 liters of oil you will use for engine flushing. DMSO thins oil significantly, so you need the thickest oil available. For this reason you cannot use flush oil as it is already too thin. I used 20W-50 (couldn't find W60, otherwise I would work with it). The oil manufacturer, standards, etc., aren't important, nor whether it is synthetic or semi-synthetic or whatever else. You aren't going to drive the car with this oil. We need fresh oil for maximum dispersing ability to hold dirt. DMSO doesn't mix well with oil unless it gets hot, so you need to heat it up to 60 C or above. Pour into a bottle with oil and heat it up, shaking it occasionally to make it homogenized. Immersing bottle in hot water works well. If you use a PET bottle, keep in mind PET plastic shrinks when heated, so bottle volume decreases. Be careful opening the cap not to splash.

Drain old oil, change filter. Fill engine with new cheap oil, start engine, heat it to working temperature. Now stop it and carefully pour DMSO/oil mix into engine (use a funnel to avoid spills). Start engine again and run it on idle for an hour. Do not raise revs! Watch coolant temperature closely.

The power DMSO has removing deposits is unimaginable, I do not exaggerate. So, unlike any other products which can be dangerous to a very dirty engine risking to get sludge pieces free and clog oil passages, the amount of DMSO we put in oil is enough to dissolve any of those gunk pieces completely. Yet, watch oil pressure indicator. While running, you might hear hydraulic lifters start knocking. It is because the oil became too thin. A little increase of revs for short itme will fix it.

So, after about an hour of idling, stop engine and drain oil. It will run out like hot water, literally that thin. Be careful removing oil filter, protect engine area and everything else from hot oil spills. Let it drain completely. Do not leave engine to cool down though! DMSO gets thick at temperatures below 15 C (even crystallizes around such level). Look at that stinky tar black substance you just got out of your engine. I think very few of us have ever seen anything like that before. When that drained oil cools down, you could see how it gets thicker and bitumen-like black. There will probably be sand-like carbon fragments at the bottom of the container.

Replace oil filter and add new oil and do the same idling procedure to repeat. This time you can carefully increase revs to about 1200 RPM for a short period of time to intensify oil flow in engine, especially around pistons. Run 1200 RPM for a minute, then idle again, then repeat such procedure every five minutes. It gives time for oil to dissolve any sludge pieces. Run that way 30 minutes to 1 hour. Stop engine, drain oil, replace filter. Collect some of the old oil in a 0.5 liter bottle and look through it. If it is tar black, your engine still isn't clean. The third time you can be more brave with revving, to prolong higher rev periods. At the end of the third cycle, when you drain oil, you should see a difference as oil should be lighter color in a bottle check.

New oil filter and fill it with fresh oil. As we cannot drain every drop of engine oil, some amount of DMSO still remains, so drive your car moderately, avoid red zone revving, and change oil again in 300-500 km. Now you are done. Keep in mind, even after you finish the procedure and flushed all DMSO from engine, new oil does cleaning work on remaining deposits. On most stubborn ones, pistons and oil rings, so you have to change oil aggressively a couple of times after this procedure, the same as you would after using BG or LM.

For very dirty engines, you might find out that even after 3 procedures you still get very dark drained oil. It means there is still a lot of dirt to be removed. To realize the cleaning power of the substance, have a look at the oil cap. It doesn't have direct oil flow on it, yet you will see an obvious difference.

For those who believe their engine is clean (as example, you dropped oil pan recently and there are no signs of sludge/tar), or if you have a full service history and are sure that oil was changed regularly and your mileage is very low, you might try a light version of this procedure - adding 50 ml of DMSO (same way, mixed with oil and heated) into engine before oil change, as engine flush, and see the results. Even 50 ml will thin oil drastically, so do not rev engine! This light procedure can be run as preventive cleaning once in a while, the same way you could use BG EPR or LM engine flush.

A few things to mention. Why I insist on repeating procedure rather that try it once and then just drive it? There is a chance of some sludge chunks softened by initial cleaning, higher revs could move the chunks and cause oil passage clogging. If we run cleaning with high concentration of DMSO and low revs, even moved pieces will be dissolved and won't harm.

As mentioned, DMSO is a very powerful paint stripper, so if engine has a painted oil pan (like some Japanese or American cars), it will remove paint as a film and clog the oil pump screen with catastrophic consequences. M54 is safe this way; the only painted part is the dipstick pipe. To be safe, I would take it off the engine and remove the paint on lower part of pipe (one which is below o-ring).

After this procedure is a good time to replace the two small o-rings on the oil filter stick. Rubber gradually swells in contact with DMSO, but it will not fix leaking seals. Moreover, if you have an old OFH gasket, it might start leaking soon after this procedure. Nothing to worry, just replace it in such case. Valve cover gasket will unlikely be affected, unless it is really old and already sweating.

Part two for combustion chamber cleaning to follow soon.
 

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So, not detrimental to the rear main seal, which will be my primary concern?

I work with DMSO frequently (more often as cryopreservative in cell biology than as a solvent), didn't expect it to be available for sale to the general public, but apparently it has its benign uses.

There is a general rule with very few exceptions- if an organic compound isn't soluble in DMSO, it isn't going to dissolve in anything else. So, not very surprised it's been used as an engine cleaner in Russia...
 

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Discussion Starter · #5 ·
So, not detrimental to the rear main seal, which will be my primary concern?

I work with DMSO frequently (more often as cryopreservative in cell biology than as a solvent), didn't expect it to be available for sale to the general public, but apparently it has its benign uses.

There is a general rule with very few exceptions- if an organic compound isn't soluble in DMSO, it isn't going to dissolve in anything else. So, not very surprised it's been used as an engine cleaner in Russia...
Two month ago I could order a gallon of DMSO form USA on Amazon.
In UAE I can buy it in horse supply store, in 16 Oz bottles.
So, not detrimental to the rear main seal, which will be my primary concern?
All engine seals are pretty strong. And, as they aren't constantly submerged, I see no risk. There were experiments to soak seals in pure DMSO, but obviously, concentration is much higher this way. You could see some softening then, but it comes back to normal condition soon after seal is out.
 

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Are those engine flushes, are they not bad for engines and all internal parts, heard that they are very chemical so can even damage some things, was recommended just do the oil change more frequently and it would clean all good :unsure:. A good oil, have the cleaning stuff, to clean the engine, so maybe you change it regularly, it would clean the stuff build up
 

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Are those engine flushes, are they not bad for engines and all internal parts, heard that they are very chemical so can even damage some things, was recommended just do the oil change more frequently and it would clean all good :unsure:. A good oil, have the cleaning stuff, to clean the engine, so maybe you change it regularly, it would clean the stuff build up
The commercially available engine flush products such as the above mentioned BG, Liqui-Molly, are tested thoroughly, both by their manufacturers as well as customers. These shouldn't cause damage when used according to instructions.
The second half - are these procedures necessary - is not as clearcut. In an ideal world they shouldn't be, but in reality people often have to deal with used cars with unknown maintenance history and obvious signs of neglect.

Our own engines rarely look dirty when inspected top or bottom side, but even then they do have the tendency to clog the oil control rings, a process that once initiated,
only gets worse as the regular oil detergents seems to be insufficient to reverse it.
If you can clean up the oil control rings and thus eliminate oil consumption with chemical engine flush as respected forum members have reported, I'd say it is worth the shot.

The 5% DMSO flush described in this thread is something else, probably devised out of necessity in Russia, where people got used cars imported from EU or Japan, then had to drive them in seriously cold Winters...
 

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To my surprise this chemical is readily available in Australia.

It does sound pretty drastic though. People worry about chunks of debris blocking oil ways etc, but I also worry about the dissolved grit running through the motor, even the super fine stuff that can pass through the oil filter. I'm still open to it though, as it would be great to dissolve anything on the oil pickup strainer in the sump, which is often overlooked and can be a problem.

So are you suggesting to use basic mineral oil like 15W40 for this procedure? It would certainly be cheaper if it needs to be flushed 2-4 times.

I like the idea but am a bit wary.
 

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To my surprise this chemical is readily available in Australia.

It does sound pretty drastic though. People worry about chunks of debris blocking oil ways etc, but I also worry about the dissolved grit running through the motor, even the super fine stuff that can pass through the oil filter. I'm still open to it though, as it would be great to dissolve anything on the oil pickup strainer in the sump, which is often overlooked and can be a problem.

So are you suggesting to use basic mineral oil like 15W40 for this procedure? It would certainly be cheaper if it needs to be flushed 2-4 times.

I like the idea but am a bit wary.
id say you can go this ultimate engine flush, but be careful, il try simple things like frequent oil change, then simple engine flush, looks like liqui moly is a good one, and might not cause any problems, I might even do the flush with this liqui moly one on my next oil change.

918108


its a good DIY though, for everyone who want to try the ultimate flush way, nice DIY Anticdubai
 

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Discussion Starter · #11 ·
Are those engine flushes, are they not bad for engines and all internal parts, heard that they are very chemical so can even damage some things, was recommended just do the oil change more frequently and it would clean all good :unsure:. A good oil, have the cleaning stuff, to clean the engine, so maybe you change it regularly, it would clean the stuff build up
Forgive me for using that example again: you have a frying pan which you wash thoroughly after every cooking with mild dishwashing liquid. It stays clean for years. Now the same pan, but you wash it occasionally, or just flush it with water. After a few months it is covered with baked residues. Now you try to wash it off, but it won't get clean without scratching, powerful degreaser, etc. Pretty much the same process happens to our engines. If one changes oil often from the beginning, the engine remains clean for very long time. If rings are baked, no oil change could fix the problem. At some point even a specially formulated engine flush is simply not enough.
 

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Discussion Starter · #12 ·
To my surprise this chemical is readily available in Australia.

It does sound pretty drastic though. People worry about chunks of debris blocking oil ways etc, but I also worry about the dissolved grit running through the motor, even the super fine stuff that can pass through the oil filter. I'm still open to it though, as it would be great to dissolve anything on the oil pickup strainer in the sump, which is often overlooked and can be a problem.

So are you suggesting to use basic mineral oil like 15W40 for this procedure? It would certainly be cheaper if it needs to be flushed 2-4 times.

I like the idea but am a bit wary.
Any cheap oil will do its work and it is truly irrelevant if it is mineral or semi-synthetic or fully synthetic with nano molecules smart protection or whatever else could be promised by manufacturer. Main criteria for us is hot viscosity (and the price). As DMSO will thin oil drastically, it is safer to use as thick oil as you can get. Ideally w60. I couldn't get any, so I used 20w50.

No need to worry about super fine particles going through the filter. First, you are using a new filter with every flush. Second, you do not rev the engine to normal level you usually do while driving. Third, fine particles pass through filter anyway and every day, and those are pretty much irrelevant.

If engine is covered with sludge all around, like on that picture (thanks Google), using DMSO will be the only option, before disassembling engine and cleaning every part separately. At that rare condition, using such method obviously could be risky, so your work is supposed to be done with constant control and in many stages with frequent washing solution changes. Also, I would increase DMSO concentration to up to a liter for 2 gallons of oil.

918136
 

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Discussion Starter · #13 · (Edited)
Our own engines rarely look dirty when inspected top or bottom side, but even then they do have the tendency to clog the oil control rings, a process that once initiated,
only gets worse as the regular oil detergents seems to be insufficient to reverse it.
If you can clean up the oil control rings and thus eliminate oil consumption with chemical engine flush as respected forum members have reported, I'd say it is worth the shot.
That is correct!
Before going whole nine yards with DMSO, I did try BG EPR three times, the way @MrMar suggested, and then LM engine flush pro twice. No results. Clearly those flushes aren't powerful enough with my case. Engine never was neglected, but high mileage, long service intervals for over 500K km, and Castrol oil made conventional products ineffective.
Now, after Dimethyl sulfoxide cleaning, oil consumption went from more than 1L/3k km to less than a liter per 6K. For engine with my mileage I see it as very decent result. (doing light flush with every oil change now, so there is chance consumption will decrease even more, but obviously there is a limit by ring wear).
 

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Like I said, I'm open to it.

I think I'll go with a couple of normal oil changes and some highway runs first. This actually would've been a good thing to do before I started working on the car, right after I picked it up.

That's a DRASTIC case pictured above. I was worried about a couple of grams of crap...that's got to be almost a kilo of mud there!
 

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Discussion Starter · #15 ·
That's a DRASTIC case pictured above. I was worried about a couple of grams of crap...that's got to be almost a kilo of mud there!
Major risk with such badly neglected engine cleaning is not a sludge, but coke deposits, which are harder to dissolve than jelly-like putty. That is why high concentration of cleaning compound and idle run is important to minimize possibility of clogging.
 

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Discussion Starter · #16 ·
Like I said, I'm open to it.

I think I'll go with a couple of normal oil changes and some highway runs first. This actually would've been a good thing to do before I started working on the car, right after I picked it up.

That's a DRASTIC case pictured above. I was worried about a couple of grams of crap...that's got to be almost a kilo of mud there!
You could first try BG EPR with oil change, as it is definitely powerful flush. You just probably need 1,5 can, and run it first time for longer . Instruction says 20 min @1200 rpm. I would do an hour or idling, just to be safe. That way won't be very effective for proper oil rings cleaning, but will clean engine in general. Then oil change and another one within less than 5K km. If thee is no significant oil consumption, such procedure will keep engine healthy.
1200-1500 pm is important in order to provide more intensive flow in rings area, yet not loading engine bearings; but it is better to repeat process than to try to get all at once.
 

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Discussion Starter · #17 · (Edited)
Thanks but I'll pass
Not a problem, of course. I do not push anyone to follow process I describe. I went long way from ''no any flushes ever in my engine'' and ''25k Km between oil changes is good, as BMW engineers are not stupid'', and also ''Castrol only, nothing else, as my car deserves the best and any other brand is deadly dangerous'' to using much cheaper oil with 5K intervals and certain flush procedures, based on my experience and understandings of processes and what they lead to.
 

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Any cheap oil will do its work and it is truly irrelevant if it is mineral or semi-synthetic or fully synthetic with nano molecules smart protection or whatever else could be promised by manufacturer. Main criteria for us is hot viscosity (and the price). As DMSO will thin oil drastically, it is safer to use as thick oil as you can get. Ideally w60. I couldn't get any, so I used 20w50.

No need to worry about super fine particles going through the filter. First, you are using a new filter with every flush. Second, you do not rev the engine to normal level you usually do while driving. Third, fine particles pass through filter anyway and every day, and those are pretty much irrelevant.

If engine is covered with sludge all around, like on that picture (thanks Google), using DMSO will be the only option, before disassembling engine and cleaning every part separately. At that rare condition, using such method obviously could be risky, so your work is supposed to be done with constant control and in many stages with frequent washing solution changes. Also, I would increase DMSO concentration to up to a liter for 2 gallons of oil.

View attachment 918136
How can you check the engine condition for deposits and sludge? You just open the head? Can you do this on your own? I mean I want to make sure that the engine actually is dirty and needs a flush or Ultimate flush..
 

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How can you check the engine condition for deposits and sludge? You just open the head? Can you do this on your own? I mean I want to make sure that the engine actually is dirty and needs a flush or Ultimate flush..
Not so sure about "opening the head", but taking the rocker cover off would give you some indication and isn't too big a job. Even better if you had a leaky gasket that needed doing, but if it didn't I'd leave it be and do a flush anyway.

If you look above to the OP's answer to my questions, you'll see he recommended starting with some oil changes and a standard commercial oil system cleaner first.

The whole idea of flushing is that it cleans deposits you can't see without tearing down the entire motor.
 

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Discussion Starter · #20 ·
How can you check the engine condition for deposits and sludge? You just open the head? Can you do this on your own? I mean I want to make sure that the engine actually is dirty and needs a flush or Ultimate flush..
Inspecting engine condition by removing valve cover , unfortunately, isn't too informative. Of course, if engine is neglected, you could see scary picture, like one posted above. But, in most cases, you witness fairly clean surfaces, no deposits, rather than yellow or red/brown plating by layer of polymers from oil being used.
The main task is to dissolve lacquers/ baked deposits in a grooves of oil rings and drainage passes of rings and pistons. And it is not easy to achieve, as such deposits are hard to dissolve, since it is limited way to deliver active substance to problematic areas. If rings are stuck, all the gaps /groves are coked and there is no oil flow there. That is why conventional engine flush products are ineffective, never mention washing package of oils.
Ant that is where DMSO, with its ability to dissolve organic compounds, comes at stage. And, of course, on its way to work on pistons' most stubborn deposits, it also cleans everything getting in contact with oil. That is why process is cut in few similar stages- first, to remove large deposits, if any, to avoid any particles to clog oil passages, and then safely to increase revs to provide higher pressure and flow at the bottom of pistons and around oil rings.
 
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