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Marvel Mystery Oil


MAC

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I know that oil addatives are generally looked upon as snake oil, but I must say that Marvel Mystery Oil cleared up engine knocking that was present when first staring. It only took a couple hundred miles. I put in two quarts (25% of oil capacity) and so far I like the results. Actually, a little more than 25% since oil capacity is 7.5 quarts. Marvel has been around since 1923. I currently have 263K plus miles on the engine and it runs good--except I need to fix a vacuum leak. If the knocking is gone for good it gives me hope that I can go another at least 50K or more. I think I'm going use Marvel from here on out to keep the engine clean. Well...Actually, I hold off on the final verdict until I see whether I end up with leaks.

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There are two types of knocking: metallic clacking, like piston slap, lifter clack, etc., and carbon-caused detonation or clacking against the head. If the knocking did not go away immediately, it was more likely carbon on the pistons. If it stays away after the next oil change, it definitely was carbon.

I'm assuming that you don't have any codes. A vacuum leak can be a partial cause of detonation, but you will likely see a P0171 or P0174 or other lean mixture code.

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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A little marvel in the fuel quiets, lubricates and cleans the fuel injectors. Another additive that works in the oil is motor honey - but i wouldn't mix it in with a batch that has marvel already in it. I suggest the motor honey to owners who have the oil light flicker or recipients of the "STOP ENGINE" message due to the oil indicator staying lit.

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A little marvel in the fuel quiets, lubricates and cleans the fuel injectors. Another additive that works in the oil is motor honey - but i wouldn't mix it in with a batch that has marvel already in it. I suggest the motor honey to owners who have the oil light flicker or recipients of the "STOP ENGINE" message due to the oil indicator staying lit.

Quiets a fuel injector?

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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I haven't used Marvel Mystery Oil in a number of years, but I used to put just a little (about a cupful) in the oil at every other oil change...

Did it for years and years... never had any engine trouble at all..

Thanks for the reminder, I'll try to remember to pick up a can the next time I go to the store..

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Motor Honey and STP Oil Treatment are viscosity increasers. I've been known to use STP gas treatment if there seems to be a bit of water in the gas. I don't have any idea what Marvel Mystery Oil does for the gas, or the oil; it seems to be a detergent for gasoline that also can help the oil clean up sludge and deposits. I just read a thread over on BobTheOilGuy where someone mentioned MMO in the gas clearing up a carbon clack on a Northstar. My way of keeping the carbon at bay was to use 92/93 octane gasoline, usually top-tier, and a bit of a lead foot.

The MSDS of MMO lists Naphthenic Hydrocarbons about 75%, "Mineral Spirits" about 25% and a trace of p-dichlorobenzene or ortho-diclhorobenzene, a chlorinated hydrocarbon; the rest is a mystery. The MSDS seems to indicate that there are 16 ingredients, designated by code name such as MM007.

Seafoam lists hydrocarbons and isopropyl alcohol in its SDS, so it should be good at picking up water in the gas and water/sludge in the oil. I believe that STS gas treatment includes methanol as an effective way to absorb small amounts of water in the gas.

I keep a can of techroline around as gas treatment. I'm far more likely to use it in the motorcycle for Spring cobwebs than in either car.

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Take a whiff of MMO; it smells of oil of wintergreen, now whether this is an active ingredient or just for smell I don't know but I believe oil of wintergreen was used to dissolve 'cruds' of a variety of petroleum products (if you believe my buddy, ex-Senior Chief, Instrumentmen).

Chuck

'25 CT5, '04 Bravada........but still lusting for that '69 Z-28

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I keep my Deville, and the wife's van in tip top condition. Both idle and run real smooth and quiet. When running, the most noticeable sound seems to be the clatter/clicking of the fuel injectors. After adding 8 ounces of mmo to the gas, that clatter coming from the top external of the engine quiets significantly. The next most noisy part of both vehicles is the belts. From inside the vehicles, you barely hear the engine running.

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Oil of wintergreen is methyl salicylate, which in sufficient quantities can soften old rubber, but I suspect that its use in MMO is just to mask the naptha odor.

If the noisiest part of your Northstar is the clacking of the fuel injectors, perhaps you could renew the layer of foam under the beauty cover. That can help reduce intake noise and also keep the intake manifold a bit cooler. Be sure and avoid a flammable foam, like untreated polyurethane.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Yes, Naphthenic Hydrocarbons or heavy naphtha, pretty much the same kind of solvent used in many of these after market treatments. I've seen the Gumout form of this work absolute wonders in quieting down stuck lifters in a police car (pushrod) engine once, the effect was immediate.

I doubt that modern engines using the recommended oils and viscosity would ever need MMO, but who knows. I DO know that a mixture of STP and MMO (proportions will vary) make a terrific slide lubricant for a 1911 .45 ACP.

Never underestimate the amount of a persons greed.

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Yes, Naphthenic Hydrocarbons or heavy naphtha, pretty much the same kind of solvent used in many of these after market treatments. I've seen the Gumout form of this work absolute wonders in quieting down stuck lifters in a police car (pushrod) engine once, the effect was immediate.

I doubt that modern engines using the recommended oils and viscosity would ever need MMO, but who knows. I DO know that a mixture of STP and MMO (proportions will vary) make a terrific slide lubricant for a 1911 .45 ACP.

I thought I was the only one that used that...and that reminds me, I'm out of it...:):)

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I would think that MMO as a gas treatment to clear carbon deposits and such might be valid. I would be careful, though. GM has cautioned against gasoline additives because solvents in some of them can damage the fuel pump in DFI engines, which, these days, is all of their engines.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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I would think that MMO as a gas treatment to clear carbon deposits and such might be valid. I would be careful, though. GM has cautioned against gasoline additives because solvents in some of them can damage the fuel pump in DFI engines, which, these days, is all of their engines.

I have used it in the gas tank on my chevy for over 10 years. When i replaced the head gaskets, the cylinders were absolutely covered in carbon - except the cylinder where the coolant was seeping in as it was clean down to the metal with white powder in it. The only thing that cleans carbon off cylinders (imo) would be spraying a fine mist of water into the intake of a hot engine. Although i am not sure i would do this to an extreme like pouring it in, but a mist will probably help without doing damage.

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I also often wondered if cold carbon rap on some cars helped contribute to head bolts and head gaskets failing. After all, that rapping force has to be exerted on something. I believe that something (being the heads) compromises the head clamping forces.

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