Who needs Bob’s the Oil Guy when we can wax on forever on this subject here?
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I recently got a 2006 e450 with the 6.8 Triton V10. It’s got 142k miles and my first trip of 160 miles cost me half a tank of gas. Had my oil changed, filled the gas tank and added a quart of MMO a week later and legit, it cost me a hair over a quarter tank to make that same 160 mile trip. I’m no engine expert, and this is my first big engine (I’ve been a classic vw owner since '98), but there’s something about this snake oil. I only used it every other oil change in my bugs, and I’ve only used it once in my e450. My husband says I shouldn’t use it because it will eventually damage my engine. He’s a chef, not a mechanic. Any insight on this? I’m really wondering if it could cause damage if I continue to use it as a fuel additive…?
Don’t fix it if it ain’t broke.
After 7 year Mr. Used may not even still have the vehicle.
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oops, here I go again… 
Hi Freejojoey:
Welcome to the site.
Did you add the 1 quart of MMO to the engine oil or to your gas tank?
There are lots of variables that need to be considered in your two 160 mile trips. Some include travel speeds, air temperature, elevation changes, did the mechanic at the garage who changed your oil fill up under-inflated tires, the quality of the fuel you refilled with, and I’m likely missing several things.
I believe your vehicle has a 35 gallon tank. If what you’re saying it correct, then it got 9.1 mpg on your first 160 mile trip, and it got 18.3 mpg on your repeat trip.
MMO might help in the “fraction of a mile/gallon” range. It’s difficult to see how it would double your mileage.
In order to get better data, try running your experiment for a much longer period of time. Drive it for 2 months without MMO, and then drive it for 2 months with MMO. Let us know what you find.
Thanks and welcome.
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Definitely going to take your advice on the 2 month test. I was told when the oil change was done it was a “fuel additive”. I actually think what was put in my tank was a different brand other than MMO. My main reason for visiting and posting to this thread was to get to the bottom of whether or not MMO would cause long-term damage to my engine if I continue to use it as a “fuel additive” every other full tank of gas. I usually fill up my tank when I visit a gas station, whether it’s topping it off before a trip or filling it on empty.
There’s no way in ___ that an Econoline 450 is ever getting 18.3mpg
Not in this universe
Not even downhill, with a tailwind
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Agreed. It sounds like you are figuring mileage based on gauge needle movement and that does not work.
Besides, if the use of MMO increased fuel mileage by even 1 MPG the Feds would have mandated that it be added at the refinery to every gallon of gas.
Just my 2 cents, but I don’t think regular use of MMO in the fuel tank is going to do the O2 sensors and catalytic converters any favors either.
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There are way too many variables (wind, tempura…etc…etc) to make any conclusions about one trip. You need multiple trips. The more trips the more accurate picture you’ll get.
I’m not sure if MMO will harm the engine. But I’m very sure if you maintain your vehicle to the specs that’s defined in your owners manual then you won’t need it.
Another way to look at it: If it delivers, can’t hurt. Think of it as insurance. I grew up in Daytona beach at a time when “Stock Cars” were almost ‘stock’. Many used MMO. And yes I do oil changes & service @ +/- 3k miles. More cheap insurance. I have a Category 2 Y2000 Lexus SC300 w/ 80K miles. (My 3rd one - 92 & 95 earlier). I’m 85 and don’t drive much anymore - but enough. If anyone offered me $12K, I’d take it.
Any car can easily reach 100k miles these days. We’ve owned 5 cars with over 300k miles without ever using any special additives. Wifes current Lexus has over 250k miles and my Highlander has over 150k miles.
I’ve used MMO to free up my lifters with positive results and no ill effects.
I had an '84 Audi Quattro with a straight-5 engine. The lifters would eventually start hanging up and tapping. I would replace the oil and filter with cheap no-name filter and oil minus a pint, and add a pint of MMO. The lifters would free up within a day. After 100-200 miles, I would change the oil/ filter with the “good stuff” and be good to go.
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