Marvel Mystery Oil has reached 100 years in existence. It's doing just fine. This year they have even come out with a synthetic version of their oil additive.
I worked in an aircraft recip engine overhaul shop for six years. We assembled all of our cylinders with MMO. The cylinders exhibited far quicker ring seating and less oil consumption than cylinders assemble with engine oil. Our shop manager recommend MMO for engine with stuck rings and low compression. Saw many of these engines regain up to 10%-15% of their compression.
There's a reason that the airlines would buy MMO in 55 gallon drums back in the days of radial engines. They would not have spent the money for decades if it didn't do the job.
But your want less lubricity during break in to seat rings....we used to use straight grade mineral oils and stayed away from Mobil 1 in race engines for this reason, during break in. After, you want the lowest friction possible.
@@jimeditorial Straight mineral oils are all we used for the first 10-15 hours after overhaul. Cylinder assemblies were installed using MMO because it “burned off” the cylinder walls. Engine oils tend to glaze cylinder walls, especially at low rpms.
I like to add 1 ounce per gallon, per MMO instructions on the bottle... I have 215,000 miles and ZERO oil consumption at 5000 miles. (Mostly freeway miles, 60-70%)
I have used Marvels for years. Put it in the crankcase and gas tank on my Honda CRFx since new. Have never adjusted the valves and it starts easily. Engine is really clean.
Been using MMO in my cars oil and gas since the early 90's. Still driving 2 cars right now that are over 20 years old and have over 200,000 miles on them that don't burn a lick of oil. Stuff is amazing!
I’ve literally never heard any claims that MMO damages your engine. That’s just me. I’ve always used it, especially after doing engine swaps from the junk yard. Cleans everything up nice 👍🏻
If used as per directions - in moderation - it will not hurt your engine. In many cases, it seems to help. I used to put in 1/3 quart or so a week or two prior to oil changes in my last car. I changed every 3-4 thousand miles. Usually used Castrol - not sure if it was GTX or not. I know I used GTX 20-50 in the bikes.
MMO is a good thing to use on certain engines. Dodges 2.7 for example. Always add 1 to 2 quarts within 1000 miles of oil change. This particular engine is highly noted for sludge and buildup blocking the oil passages, resulting in catastrophic engine failure. The key is for any engine, to perform regular consistent oil changes.
I have a 2006 Chrysler Sebring (2.7 engine) with over 200K miles on it. The engine has been rebuilt a few years ago after losing a rod, but has a faint ticking noise I want to eliminate. Would this be a good product to try without damaging my engine? Mechanics thus far haven't been able to pin point what is causing the noise.
@@davidc6171 maybe..what kind of oil and filter are you using. I would recommend using an original equipment Chrysler Dodge filter. Cheaper aftermarket filters can in some cases restrict oil flow and starve certain areas of the engine. Especially the 2.7. Try an OEM filter, use semi synthetic high mileage low sludge oil. I personally like Mobil 1 full or semi synthetic. Then when or if your down a quart of oil 500 to 1000 miles before your oil change due mileage, add a quart of Marvel Mystery oil. It helps clean out the buildup in the oil passages and pan, ect.
@@showcasecharlie11 I last used CASTROL GTX HIGH MILEAGE oil. 5W20BK. Will have to verify if they used a Mopar Oil filter. Noise has been consistent shorty after the engine rebuild a few years ago. It is very faint and hasn't gotten worse. I no longer deal with them due to concerns I had with the engine they never addressed. Hoping it can be fixed without having to remove the engine again.
@@davidc6171 add Lucas oil stabilizer. The stuff is great. it's usually $12 a qt but at Walmart you can get a gallon of it for 27. so it's almost like getting 2 qtas free for the price. I run it in bothe my ram and my 300
I'm running 20% MMO in my 1978 Honda GL1000 right now. Its been there for about 500 mils at about 65 MPH average speed and the bike runs great. I also add two tablespoons of MMO to a full gas tank lots of times and the engine loves it. Bike runs like a jet.
I hv used mmo for 50 yrs and put 1 qt in my oil change and never had any problems ,many high mileage vehicles Mmo in my gasoline tank every time more power and no carbon build up My dad told me as a kid to use mmo regularly and get 2- 3 times more mileage out of the moter it was much cheaper than rebuilding the engine
I own a classic car dealership and the first thing we do to every car we buy is change the oil and run it for 100 miles or so and then replace all the gaskets and seals and then refill the engine with GOOD oil. We've never left it in though. May have to try that.
I wouldn’t use it on a really slugged engine it could loosen the sludge and block the oil passages. But I use 20 percent with my oil at every oil change, have had several vehicles with over 200,000 miles, when I did tear downs the engines were pristine clean inside. I am a believer.
What's more common is seals to leak temporarily while it's in there. Once back on just oil it goes away. Same may be true for burning, but it's only burning the MMO
@@chancefluke7833 it reduces oil burning, I have a 2007 scion tc and I use 20% mmo and it burns alot less oil than just using regular oil, the tc has a piston ring issue that causes the engine to burn a quarter of oil every 700-1,000 miles.
Bought a used Dodge pickup with a 318 years ago. Pulled the rocker covers off and could not believe the sludge in there...I couldn't believe the engine was still running! So I cleaned out as much sludge as I could from the rockers with my fingers. I then took a spray bottle full of Marvel's Mystery Oil (MMO) and soaked the rockers and galley as much as I could, put the covers back on, and let it set for a few days. I then started it up and let it idle to operational temp. I then drained the engine oil. Next, I put new oil in, with 20% of it being MMO. And did that for the next 3 oil changes of 3000 miles each. From then on, whenever I was about 500-1000 miles before I was due for an oil change, I would top it off with MMO (but never more than 16 oz. Sixteen years later I sold that truck to a guy who rebuilt the engine. He remarked to me later, that it was a very clean engine and he was surprised being it was a 28-year-old engine with 186,000 miles on it.
Just like it says. Its a Marvel and the Mystery ingredient's work extremely well. I add to my fuel tank of my 2009 F150 with 265k as well as do an engine flush substitute of 1 quart for appr 2000 miles before changing. I change the oil every 3000 miles on this truck. I do this every 50k miles without fail. Truck runs like a champ. I also have 65k on my 2020 F250 7.3 gas and I did the same on it at 50k miles. looking for 500k miles out of this truck before any major rebuilds.
I put an ounce in my 1.2 gallon scooter tank, also about 15% of my oil capacity is MMO. I just did this a few days ago. No problems yet and seems to run just fine
I had a 1997 Oldsmobile Bravada that had a clogged injector. While almost empty, I dumped a whole bottle of MMO in the tank and then filled it with premium. By the time I had gone through that fill up, the injector was cleared and it was running smoothly.
JihadUnplugged757 it wasn’t MMO that cleaned the injector I snuck over in the middle of the night and took out then cleaned the injector and then put it back in.
I run shell rotella 15w40 in my vehicles and I might consider a quart of MMO next time I change oil, or drain a quart and add MMO if it gets severe cold this winter.
Marvel Mystery Oil has been around since 1923, so it must be doing something right. I have been using it since 2016 in the gas of my car and truck at 4 ounces of MMO for every 10 gallons of gas. My highway miles per gallon has increased 1.5 to 2 extra miles per gallon since using MMO. Walmart sells the quart (32 ounce) size for $3.88, and at that price, I am actually saving money using MMO in using less gas. Plus the added benefits of MMO cleaning the fuel system, a much smoother idle, and lubricating the top end of the cylinders and the fuel pump. I have also added a quart of MMO to the oil of my 2002 Chevy truck when I am about 4 to 5 hundred miles from needing an oil change, to clean some sludge out of the engine.
Marvel Mystery Oil has not done anything to my catalytic converter. I have used it for more than 3 years at 4 ounces for every 10 gallons of gas, which is the recommended amount.
@@kcmaldonado3948 So far i've saved 2 cars and 1 truck's cats that were throwing codes that after an inspection/diagnostics was told would need new cats. in each case knowing i had nothing to loose i dumped 1 gallon of pure acetone and one entire bottle of MMO in to the gas tank, filled the tank up with premium gasoline then hit the highway, dialed in the cruise control at 55 mph (your mpg's will actually drop with this mixture but that's ok, next tank will not only recoup but show gains!) and drove until the entire tank was gone. within the next 50 miles of regular city driving check engine lights turned off no more cat issues even 8 years later, still same cat, still running perfect, but in each case i did recommend they start using MMO in the fuel regularly or my preferred mix of 2 oz MMO + 2 oz acetone per 10 gallons. One of those vehicles (the truck) has now ended up in my hands 6 years after the original cat treatment with MMO and still running perfect, same cat, no codes, starts instantly and exceeding the epa MPG ratings.
I put a FULL quart of MMO in my E39 BMW every 6 months with half of a tank of gas. I then drive it 80 miles on the highway. I've done this for ten years....to the same car...
I had a valve sticking on my old Jeep I drained out 1/2 qt of oil, Then added 1/2 qt of mmo to the fuel tank and 1/2 qt mmo to the oil Started engine, within 30 seconds the noise when away, heard it for a few seconds a couple of days later, That was years ago never heard the noise again, at oil change I always add 1/2 qt mmo to oil and to gas tank All I can say is it worked for me! No time here but I had tried everything to stop the sticky valve, next step was a valve job on a remanufactured engine with less than 5 k miles,
The problem with any flush, including MMO, is the potential for sludge and deposits, once mobilized, to block small oil passages and galleries in an engine. Not a big risk on a lawnmower, but not something I would recommend for a motor vehicle engine with variable valve timing or displacement on demand that is operated by oil pressure, if significant sludge/deposits are suspected. In those cases, if sludge is known or suspected, it's best to simply start using high quality oil, and change it more frequently than the recommended service schedule to gradually erode sludge and deposits. That said, as preventative maintenance on a well maintained engine? MMO is not necessary, but probably not harmful either. As for this test, it has value in that it demonstrates MMO can clean engine deposits. I personally would not assume that because no apparent harm was done to a $50 lawnmower, that MMO would be a good idea in a vehicle worth thousands or tens of thousands of dollars. YMMV.
I've always got great results from MMO, before a oil change I would dump out a quart of engine oil, replace it with a quart of MMO go and hot rod the vehicle around for a while getting the engine good and hot, drain it all out, replace the oil filter and add new oil,,, seems to work very well, engine seems like new again !!!
You don't hot rod it while you have Marvell Mystery oil in the engine. All you do is let it idle for 10 or 15 minutes then change the oil. MMO is primarily detergent not oil. Which is why it does such a good job at breaking loose gunk etc. But you should never run your engine above idle.
MMO is actually safe enough to drive your car normally on. Just only use one quart of MMO and the other 5 quarts can be your favorite oil (in a 6 quart oil pan that is). You can drive it for 5,000 miles that way and change the oil and filter normally.
I knew a guy who became really ill, ended up in hospital and even lost a leg through gangrene. He started drinking 50ml of Marvel Mystery Oil in every cup of coffee, and within 9 days he was was out of hospital. Furthermore, after 2 years his leg had grown back. It really is incredible stuff.
The engine oil light started coming on in my wifes 5.7 Hemi, so I immediately went to the part store and bought a quart of Marvel mystery oil and put it in the engine. After 30 minutes of driving the light stopped coming on. Great stuff. I'm going to leave it in until next oil change to get all the gunk out of the engine.
If the oil light came on then it was low on oil more than likely, if the low oil pressure light came on then I was full of sludge and most likely would run much longer.
MMO really isn't a "flush". A flush is something you add to your motor right before an oil change, run the engine for 10 minutes, then drain out. Those kind of flushes have a high solvent level and while they clean well, they're not safe to drive your engine on. MMO is an oil additive that is mild and will help clean your motor over time, but is safe to use with your engine oil for 5,000 miles, so long as you don't exceed 20%.
@@bayfinest1938 It states on the bottle not to exceed 20% of MMO in your oil pan. What that means is if your oil pan capacity is 5 quarts, then you are ok to run 1 quart of MMO with 4 quarts of motor oil. That would be a 20% ratio. You can also run a 10% ratio as well, which is what I normally do. Hope that helps.
If ever I do a weird job that I need weird oil for… marvel… every time marvel. I use to think it was a gimmick… nope the stuff is liquid magic. I unsized motors, flush engines and also add it wherever I can! Just does such an amazing job keeping the engine free of sludge and running great. Great stuff
I've used it in a Chevy 350 before that the lifters were gunked up after bout 500 miles the engine was cranking and idle smoother. The oil with in bout 1,000 miles was black. Changed it with new filter went 3,000 miles and changed it again. It was a remarkable difference. I then ran some Rotella t4 10w30 by it self for next 3,000 miles its clean not spotless but so much better than it was my oil pressure guage is showing higher than it use to now. Im using havoline high mileage 10w30 now and it runs like a champ. My advise for marvel mystery is it thins oil out to when i used it i went to 10w40 i recommend if you use it with 5w20 best probably to step up to 5w30.
@@NATESINTERACTIVEAUTO no problem i was scared at first but to use it but my dad and granddad said they used it for air tools and rust and way back when what did i have to losse i do remember my dad saying his brother used kerosene as a flush one time said it worked good only problem was the sludge stopped up oil sump and blew motor up 😄
My great grandfather was in the 1st armored division "Old iron side", was at first a tank mechanic, then tank commander, and then after getting hit by a artillery and losing his hearing for a month he was a cook. My papaw(his son) told me that he said they used mmo and pretty much used it as often as they could when they had time to do maintenance and oil changes, they used it for alot of things besides engine oil flush as well. He said it works miracles in keeping engines and equipment in good running order. (Now remember oil was no where near as good as it is today and I'm pretty sure that's why he used it as often as he did. But with today's oil, I'd use it every 50k-100k miles depending on how often you change oil. If you change oil in long intervals definitely closer to every 50k. I change my oil every 5k. So I try to flush about every 100k miles.
@@Cdub541 depending on the engine yeah. Some engines are built with better materials than others. Or are built to actually last. There's a bunch of different reasons, some good, some bad, but it is what it is.
Change your oil every 3k mis with full synthetic people. It's dirty enough then. Sure they claim it'll protect longer but don't do it. 1.6 million miles on my Toyota original motor and trans. Yes I use mmo in gas and have used it as a pre flush before oil change. It's just kerosene and trans fluid people
The problem with engine oil flushing on a slugey motor is the slug gets in the oil pump pick up screen and cuts oil flow too the engine and could cause bearing too burn up
I throw an ounce in my gas every other week and 4 ounces in my oil every oil change in my Harley. Finally did a tear down and put some s&s heads on it last year and a full rebuild while I was in there. At 63,000 miles.. the motor looked like it only had 5,000 miles on it. I was VERY impressed. I know the oil I run isn’t 100% to thank for that because we did the same thing to my dads bike a couple months ago and he doesn’t add anything to his bike. His motor was pretty nasty inside, idk how his exhaust valves were functional to be honest. Means the marvel is the real champ in the equation. He now uses it religiously haha I say, they’re pretty great from my experiences.
@@bobbyg7269 I just run maxima oil. I use them for all 3 applications on my bike, the oil, trans and primary. They’re pretty consistent and I get good results from them so I just stick with it.
I’ve never had an issue using it. I flushed every single one of my jeep Cherokee’s and the only thing that happened was the cylinder head and crank case were all spotless and they manage to stay that way because I did it every two oil changes. But that’s also a Jeep 4.0 liter, those things will run on unicorn piss and hairspray. And I wasn’t worried about it thinning out the oil since I ran Delo 400 15w-40 all the time. And it does work really well on fuel systems too. My 76 F250 had a bunch of random crap in the carburetor and it quit running well, so I dumped a bottle of this in the tanks and after half a tank it was gone. I pulled the top off the carburetor, it looked almost brand new. But you can also do the same thing with plain old ATF.
I been using marvel oil in all my oil changes and to gasoline at every fillip since 1972 . here we are in 2024 and now have my first foreign truck, a Tacoma and the tradition is on going with marvel mystery oil which used to be made in portchester,n.y. . all my new vehicles have received well over 200 thousand miles on them and my 94 dodge Dakota with 312k miles and still on the road in duchess county,n.y. with 400 plus miles . always use marvel and it will keep everything clean without ever a hydraulic lifter tick and no stuck valves . any other opinions about this mystery could never convince me that I am using the best additive and need not buy all the crap on the shelves . another example is my 1988 MTD snowblower which use with every snow storm . that too loves marvel oil . 100 star rating from me . *********
I agree with you on everything you said. I've been using it since about 1965. I never use more than directions call. More is not better. I still have people telling me it's no good, but that is usually while they are riding in my old truck to drop or pick up their vehicle at the mechanic.
with all the so called experts out there the fact is marvel is king . add 5 ounces in tank with every full fill-up and 6 ounces added with every oil change .52 years of use with never an issue and a smooth running engine that never seen a breakdown is all the proof any one needs to know .and please don't do these new 10k mile oil changes . your destroying your engine .opp for your first oil change at 2k miles, then 5k and then 10 k. then every 7k oil changes thereafter with only full syn oil and your 6 ounces of marvel to insure a long long life with your vehicle . happy motoring .........@@mikemorgan5815
I just add it to my engine oil in the recommended proportion. It has worked to keep my engines (vehicles and lawn care equipment) crud-free. !!!! For me........This product has stood the test of time !!?
I've never thought that adding a quart to your oil change every 2-3 oil changes ever done anything but good ... All my engines got at least 250,000 miles . Yeah , I don't have much money . lol
I’ve used MMO for years with zero issues. I used it like people do Seafoam. Years ago I used to dump it down the carburetor until it smoked and hot soak. Now I just use in the oil about a week before a oil change. Once I drain the oil i pore a quart of cheap oil through the motor before I change the filter and add new oil. It works for me for years now. Not changing!
I've been using MMO for years, it's best using it exactly like it says and my engine is super clean like brand new clean. I also use it in the gas. Best stuff I have used.
I buy a lot of 300 dollar beaters and the first thing I do is put a quart of Marvel Mystery Oil in them drive them for a couple days and then change the oil. And each time I change the oil, I add some and drive it for a day or two before doing the change, it clears up all kinds of valve train noise, loosens sticky rings, I have had good luck with it myself...
No I haven't heard of a flush or MMO damaging an engine! But when I was in the parts business we sold alot of such items to add to the oil. Yet when I asked the most trusted mechanic's around they said if the manufacturer didn't recommend it in their manual then don't use it! Those guy's are engineers and know what's best for their engine's! Cheer's..... Ps I use MMO in my gas and once in my oil!
I use MMO regularly mixed with full synthetic motor oil to my 2012 Nissan Murano see the internal metal shine look fresh unlike I saw some cars or trucks had gum sludge dark brown in the engine built up . Happy with MMO .
Marvel Mystery Oil is not a flush...... However by adding one quart to you oil change schedule can remove harmful deposits. When you change the oil you will see black oil pouring out. By the second or third oil change there will be less negative deposits and improved performance and fuel economy.
You could eat off my 1969 Ford Mustang Coupe's Engine. Inside the engine 302 V-8 was so clean when we took off the valve covers it was stunning! But In 1999 it had 253,000 Miles on it & I could still pump it up to 90 MPH. Marvel was its lead substitute in the Gasoline. Protects the top of the engine internally. I ran it in both in my trucks. My 1999 F-150 has 190,000 miles on it right now. I use it in my mowers & tractors even weed whackers. I have a Wheel Horse Tractor that is 36yrs old. Use as directed!
People are saying with sophisticated new engines, like the Ford Ecoboost, twin turbo charged, direct fuel injected engines, you can flush significant amounts of carbon into your catalytic converter and clog it up, requiring a replacement. Also the chunks of carbon can get into the turbo chargers causing turbo fan breakage and more. BOTH of which are very expensive repairs. Doesn't seem worth the risk if you're buying good gas, using really good oil and changing your oil regularly.
Man I think torching those rockers might have loosened up that sludge a bit. It definitely did a good amount of cleaning though. Maybe even more than you might want in a modern engine all at once. Thats a lot of MMO for that little engine. Running much less would probably be safer. Depending on how previously neglected the engine was.
Would like to see it. I had a 1985 mustang 5.0. Used rislone at every oil change and when it over heated and blew a head gasket, i took it apart and the heads were as clean as new.
I own and operate a classic car dealership and every car we buy the first thing we do is change the oil using the cheapest "store brand oil" and add a Quart of MMO and run it for 100ish miles then change it and put some good oil in it, You wouldn't believe how clean it gets the inside of an engine and in more than 10 years we have nothing but sucess with it.
OMG! Why are people still doing this and having these discussions. I flush my engine with 50-50 mixture of water and diesel. Let it run for 100 miles and then watch my engine blow up. Now, I don't have to worry about my engine anymore. Done!
Had a Honda used a half quart of marvel every oil change when I sold the car it had 502,000 miles on it and did not use any oil and it's still running today
Today i started the MMO oil flush, (20% of 6 qt) in my 4.7 2013 RAM 1500. After turning it on, heating it up and turning it off and letting it sit for around 5-6 hours, i started the truck back up but it started funny. Sounded like it gained compression bc it didn’t crank over as long as it usually does, usually a “do-dooo-do do do do vrrrooommm” but this time is was a “do-do-vrooooom” if that makes sense. I’m gonna run it for 500 miles, see what happens. The oil i used was Shell Rotella Gas Truck, btw. Let you guys know what happens.
I was really constipated once, so I added mmo to my bowl of captain crunch oops all crunch berries- ten minutes later, I could crap thru a screen door. Stuff really works!!!
I have found that it is a mild solvent {Stoddard Solvent} for cleaning up the crankcase of dirty neglected engines but watch out for plugged oil filters. As a fuel additive it helps with sticky valves but also carbons up the spark plugs cylinder head and valve surfaces when used as directed. I pulled the heads to have a look. It has its uses, but its no miracle cure.
thanks for the video. i have over 200,000+ miles on my chevy malibu using MMO. no problems. i might use MMO in the crankcase. previously used seafoam and it's worked great. expensive.
Are use mystery murder royal all the time with great results and in fact I add even some sea foam to the mix! I recommended for turbo charged engine to help clean the blow by oil if you’re not using an oil catcher can! 😉
Anytime a motor is warm the compression is increased everything expands. Unless the rings are wore out . If you want to keep your engine clean inside . Change the oil on a regular basis . Marvel mistery oil is good for diesel fuel and carburetor motors .
I think I screwed my engine up with this stuff. It was smoother w/ MMO. So I bought more. I mostly used it in my gas. I saw the bit about 20%. I was concerned using that much, so I used 10%. I did my oil change in spring and changed it again in fall. I don't drive much, so the mileage shouldn't of been too much. Noticed white smoke coming out of my tail pipe at start up in the morning. Smelled like burned electronics. Then it clears up with a warm engine. Took it to Nissan thinking it was the beginning of a blown gasket. The car lost its 1st engine due to hydro locking. The second engine had less miles. That said, I don't have as clear of a history on it. Nissan, says they found sludge in the oil pan and will probably turn me away for a gasket replacement. I'm not exactly well off and I'm a onsite technician so I need my car. Not even sure what to do. I won't be buying another engine that's for sure. I just think this stuff is strong stuff, more than is realized. Beware.
Should have been close to three and a quarter Oz, but that's close enough. You're actually putting in 25%. Marvel Mystery Oil is not a flush. Never has been. This is not a particularly good action to test Marvel Mystery Oil when you're trying to apply it to Automotive. But it has worked fine an automotive application since 1923 when they first started bottling it.
yes, you are correct, 20% of 16 is 3.2. However, unless he drained some oil (i did not see him do that), he has a 20% solution of MMO in the engine. Yes, it's overfilled at 20oz, but with 20oz in there, 20% is now MMO (20% of 20oz is 4oz)
yes, you are correct, 20% of 16 is 3.2. However, unless he drained some oil (i did not see him do that), he has a 20% solution of MMO in the engine. Yes, it's overfilled at 20oz, but with 20oz in there, 20% is now MMO (20% of 20oz is 4oz)
Just replaced a quart or so of oil with MMO in my '12 Ram 1500 4.7, the change in engine noise was immediately noticeable. I plan to do an oil change in the next 100 or so miles so i hope it cleans as well as reported.
Mmo works been using since back in the day when it came looking like oil cans saved many many engines even some that were seized it works point blank period.
Its situational. I use it in the gas tank. Never again will i mix it with oil in the crankcase. Ever since I did that 100 miles before an oil change my engine has been burning oil at a noticeable rate. Have to add about 1 quart of oil every 1 thousand miles. Some sludge is good sludge
If you do it before you’ve been running an engine for a long time with sludge build up, you won’t have that problem. I’ve been using it in every oil change for the past 5 years, no oil loss at all. I would like to see what the inside of the engine looks like. I started it around 30k miles, maybe a little less
@ girohead-- You do not want to over fill the crankcase with oil and Marvel Mystery Oil. If the dipstick is at the full mark, I would drain some oil before adding the MMO. In my case, I have a Chevy truck that has 148k miles on it, and uses some oil. When it is a quart low on oil after a oil change, I add a quart of MMO. The MMO has quieted a lifter ticking noise and has removed some of the sludge out of the engine in my truck. My car doesn't use any oil, so I have not yet put any MMO into its crankcase. In both vehicles, I use 4 ounces of MMO for every 10 gallons of gas every time I buy gas.
If you're changing your oil regularly no longer then 6-7k miles with good full synthetic oil your engine will be clean from the additives that are in the oil. Sure adding a few ounces in the tank and crankcase will also help in keeping sludge and other contaminants from ruining your engine and fuel system. But basic maintenance is always key for success more times then not.
I'm really really interested in a test with Z-max been wanting to try this for years now but haven't seen any independent test on it. Have you any idea on it's claims????
MMO is very popular amongst the saturn community. I had good luck with Zmax additive too. 400,000plus kms logged with no oil leaks or major issues on a dohc 1.9 saturn motor using zmax as recommended from the manufacturer.