MMO in crankcase - how many miles?

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Gents,

I threw a quart of MMO in my crankcase a couple days ago (My car holds 4.5 quarts of oil). In your opinion, would it be ok to keep it in there for about 1,000 miles, or would that be pushing it?
 
I'm not a fan of using MMO for extended periods of time. It simply dilutes the excellent engineering and additive packages that comprise modern oils.

Put another way, use it to clean, drain it out and use a quality oil, without adding anything.
 
Originally Posted By: Cujet
I'm not a fan of using MMO for extended periods of time. It simply dilutes the excellent engineering and additive packages that comprise modern oils.

Put another way, use it to clean, drain it out and use a quality oil, without adding anything.

What's your definition of 'extended period of time'? Please note that I'm not talking about time periods, but am talking about mileage.
I'm going to do some traveling for the July 4th holiday and estimate that I will put about 800 miles on the car by next Monday. I put the MMO in about 20 miles ago.
So my question is would 1,000 miles be too many to have MMO in the crankcase?
 
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Originally Posted By: Phishin
I have found no ill effects in running MMO the entire length of an OCI.


+1
 
At my last oil change, I went with 4.5 qts of oil and .5 quarts of MMO, instead of a full 5 quarts of oil. The bottle says to use a full quart, but I felt more comfortable with .5 qt.

That said, I also adjusted my oil mix a bit. The car calls for 5w-20, so I used 5w-30 for the last 1.5 qt of oil to offset the .5 qt of MMO, since it's quite a bit thinner.

That was about 1500 miles ago, and the car runs great.
 
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run it and dont worry about it. the traveling will do your car some good with it in there. if you feel frisky, pull a few oz of oil from the dipstick and save them in a little party cup, pull a few more in a different cupp when your home and see tye difference in color.

i did this with a boat motor and my old harley when i got it. works wonders...
 
Will it hurt anything to add about half a quart of MMO without draining .5 quart of oil? Will it be "too full" and cause damage if I run it for 500 miles?

(Hope this isn't considered hijacking the thread. Figured it was a very similar issue.)
 
A good rule of thumb is "never overfill your ____________"

..and fill in the blank with:

Crankcase
Transmission
Bathtub


If your dipstick reads full, then wait. If your dipstick is down by a 1/2 quart, then I don't see any harm in topping off with a 1/2 quart of MMO.
 
Originally Posted By: dan765

What's your definition of 'extended period of time'? Please note that I'm not talking about time periods, but am talking about mileage.


I certainly hope you know what I meant. But, since we are mincing words, I will re-phrase. I am not a fan of using Marvel Mystery Oil to dilute a quality motor oil, ever. If it's being used as a cleaning solvent and engine flush, just prior to an oil change, so be it. But I don't want ANY Marvel Mystery Oil in my crankcase during ANY normal operation.

I'm not predicting trouble by it's use. I am questioning why people feel it's necessary to add MMO to an otherwise very well engineered oil. Certainly, you can choose an oil that will clean deposits, such as any quality synthetic, if that's your goal. It will clean quite well without any need to change the chemistry of the product. MMO is almost 1/3 mineral spirits, has a very thin mineral oil base, Some phos with no zinc (not a good combo) , wintergreen scent and red dye. Not exactly a wonderful combination of confidence. In fact, it's a whole lot of nothing.

BlackstoneMarvelMysteryOilReport.jpg
 
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I used it once. It didn't fix the problem that I first thought it did. It didn't hurt anything either during the short time I used it.
 
I wonder if Blackstone can provide UOA results that show what happens with the use of MMO. I do remember someone on this site showing higher wear metals with the use of MMO. However, that was simply one data point.
 
Originally Posted By: SirTanon
A good rule of thumb is "never overfill your ____________"

..and fill in the blank with:

Crankcase
Transmission
Bathtub


If your dipstick reads full, then wait. If your dipstick is down by a 1/2 quart, then I don't see any harm in topping off with a 1/2 quart of MMO.


Awesome, thank you. Just what I needed to know!
 
Originally Posted By: Cujet
But I don't want ANY Marvel Mystery Oil in my crankcase during ANY normal operation.

I normally don't step into these MMO threads, but I think we need to look at the history about. MMO has been around for just about forever. I could understand the desire for crankcase additives (and flushes) in the days of non-detergent motor oils, such as when this product first came out. For a vehicle running appropriate OCIs with a modern, certified motor oil, I'm skeptical.
 
Here is a follow-up question:

I've got Maxlife 10W-40 in there. As I mentioned above, it holds 4.5 quarts.

Since I took 1 quart of the 10w-40 out and replaced it with 1 quart of MMO, what is my oil weight now?
 
Originally Posted By: dan765
Here is a follow-up question:

I've got Maxlife 10W-40 in there. As I mentioned above, it holds 4.5 quarts.

Since I took 1 quart of the 10w-40 out and replaced it with 1 quart of MMO, what is my oil weight now?



Hard to say.

Remember that the solvents will flash off and the lighter oil fractions will vapourize as well,so in 1000 miles it would be tough to even tell the mmo was in there.
 
Originally Posted By: dan765
Here is a follow-up question:

I've got Maxlife 10W-40 in there. As I mentioned above, it holds 4.5 quarts.

Since I took 1 quart of the 10w-40 out and replaced it with 1 quart of MMO, what is my oil weight now?


From other threads on BITOG, MMO is roughly 10w weight.

- If my calculations are correct, at that mix (3.5 qts MaxLife 10w40 and 1qt MMO), you're looking at roughly 10w-33 ... at least at first.
 
Originally Posted By: Cujet
I wonder if Blackstone can provide UOA results that show what happens with the use of MMO. I do remember someone on this site showing higher wear metals with the use of MMO. However, that was simply one data point.


I doubt B_S would provide that info so, you got me thinking. I checked uoa's with the use of mmo and they looked good. I use/used the stuff for a long time with some great results. A golden oldie that works great for cleaning up an engine that needs cleaning. OTOH if it ain't dirty don't clean it. I've run it the whole interval in a few project car neglected engines, ticking lifters stopped ticking and stayed that way, down the fill hole looked better too. I'll still use it when needed, otherwise a good synthetic and leave well enough alone.
 
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