MMO in fuel... bad for a car with cats?

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PantherFan88

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Is there a real benefit for my fuel pump longevity and lubrication of upper cylinders with regular usage of MMO?

I am just curious as to any negative affect on the car's catalytic converter longevity, as burning an oil with my gas doesn't seem to be a cat-friendly idea.
 
I can't see any savings/longevity benefit in lacing fuel with MMO.
The factory pumps tend to run to 250k-300k on gasoline alone as lubricant.
Then the price for a replacement runs from $25 (undersized knock-off) to $300+ for the exact factory unit.
All that MMO$$$ you poured in the tank would go a long way to offset the replacement pump cost.
 
Originally Posted by vw7674
I can't see any savings/longevity benefit in lacing fuel with MMO.
The factory pumps tend to run to 250k-300k on gasoline alone as lubricant.
Then the price for a replacement runs from $25 (undersized knock-off) to $300+ for the exact factory unit.
All that MMO$$$ you poured in the tank would go a long way to offset the replacement pump cost.

Or 420,000 miles in the case of my old Sienna which has never had any sort of aftermarket additive in the fuel, ever. Same for my Honda and the ECHO, both currently at 280,000.

I've also never figured out what it is in the upper cylinder that isn't getting proper lubrication and requires a "UCL" to lubricate it.
 
Originally Posted by rekit
I've been putting TWC-3 2 stroke oil at in my Tacoma (01 v-6 250K) for 5 tanks now and ok so far. There are lots of articles on it.

https://www.ls1.com/forums/f48/been-testing-oil-91206/index57.html

That's not an "article", that is someone's opinion.

I'm sure there are standardized ASTM tests that would conclusively demonstrate the efficacy of a UCL, have you ever seen results of those tests?
 
Originally Posted by BMWTurboDzl
Yes because fuel pumps filled with just gasoline will as a rule last longer than the car itself.



For the most part. Your are correct.
 
I guess it depends...

Everything I own which pulls a load more than the vehicle weight itself (my F150 pulls 8,000 lb - 10,000 lb loads pretty often) gets MMO or TC-WIII in the gas to help keep the ring packs lubed. 100% WOT through multiple hilly areas, is very common.

My 2013 Kia Optima (GDI engine) also gets 640:1 TC-W3 in the gas.
 
MMO in the gas finds it's way into the motor oil. That alone may be reason to avoid it in some engines.

However, I do find that my Jaguar X-Type is considerably smoother with MMO in the fuel.

I don't use it, and don't believe in it. I simply added some (that I had on hand as an air tool lube) in an attempt to address a misfire that was unrelated to anything fuel or oil. Eventually I found a leaking intake manifold in multiple locations. But it did make it run smoother, no question.
 
If you drive on the first half of the tank all the time your fuel pump runs cooler. In other words try to drive half full or more especially when its hot outside. The fuel cools the fuel pump if it's mounted in the tank. I have heard that 2 stroke oil in a mower will lubricate the carb and keep things from getting sticky. I never really had any problems with fuel pumps except on a 1997 Corvette one pump would whine a little bit once in a while when it was hot out side. I also had a 1999 Ford Expedition that did the same thing. Neither of the vehicles had to have it replaced as long as I owned them.
 
I used to use various products but I probably wont use much or will just use a bottle of techron or crc fuel system cleaner once a year. Like others have said, I doubt they do very much considering our current fuel quality.
 
Originally Posted by PantherFan88
Is there a real benefit for my fuel pump longevity and lubrication of upper cylinders with regular usage of MMO?

I am just curious as to any negative affect on the car's catalytic converter longevity, as burning an oil with my gas doesn't seem to be a cat-friendly idea.


I ran MMO in my fuel for ~30k miles. It bumped my mpg's and engine performance, but both began to taper off 1/2 way through that.

Then the right cat sloughed off a chunk and partially clogged that side.
wink.gif


The truck already burned oil, so it can't be wholly attributed. but the lesson learned was to use PEA for cleaning; it bumps the MPGs about the same (or more) and cleans w/o poisoning.
 
I can't say there is a benefit to the fuel pump or upper cylinders, but it's not hurting anything except your wallet.
Regarding the catalytic converters: at the ratio you are talking about, there is no risk to the cats. Remember most major automakers claim that 1 quart every 1000 miles is considered "acceptable" oil consumption. I'd assume your vehicle is getting better than 12.5 MPG:

MMO recommended ratio: 4 oz per 10 gallons fuel

4oz oil x 1 qt. oil x 1000 mi
10 gal fuel 32oz oil 1 qt oil

= 12.5 miles/gallon equivalent (1 quart /1000 miles) at the MMO recommended oil/fuel ratio

Edit: [censored] editor took out the spaces. The equation is three fractions multiplied.
 
Last edited:
Originally Posted by Linctex
I guess it depends...

Everything I own which pulls a load more than the vehicle weight itself (my F150 pulls 8,000 lb - 10,000 lb loads pretty often) gets MMO or TC-WIII in the gas to help keep the ring packs lubed. 100% WOT through multiple hilly areas, is very common.

My 2013 Kia Optima (GDI engine) also gets 640:1 TC-W3 in the gas.



Your WOT runs if the oil is at operation temperature are actually beneficial and it's better than lugging the engine.
 
I doubt that either MMO or TCW3 does anything to lube the fuel pump in the mix ratios they're used at.

I can see them providing lubrication in the engine (intake valves, piston) where parts are at a high enough temperature to evaporate fuel and leave the oil behind.

I can also see a benefit in carbureted engines where a light coating of oil is probably left on the butterfly after shutdown that might help lubricate bushings or where it might provide protection if the engine is left to sit for a while and fuel in the float bowl begins to evaporate.
 
TC-W3 at 1 oz per 5 gal. in my 2016 frontier V6, auto trans. Purolator Boss PBL 14610. which is 1/2 longer than BOSS PBL4612 on my GF 2013 sentra. i want see if the PBL14610 will fit the 2013 sentra.
 
Originally Posted by Linctex
I guess it depends...

Everything I own which pulls a load more than the vehicle weight itself (my F150 pulls 8,000 lb - 10,000 lb loads pretty often) gets MMO or TC-WIII in the gas to help keep the ring packs lubed. 100% WOT through multiple hilly areas, is very common.

My 2013 Kia Optima (GDI engine) also gets 640:1 TC-W3 in the gas.


I made a post about it in the other thread, but using TCW3 in the gas of my truck at 1oz/5gal lowered oil consumption while towing significantly. Even during one section where I had my foot firmly planted on the floor with the engine at 4K for a few minutes.

With oil consumption raised from 1qt/100 miles to 1qt/1500 miles towing, even with the added TCW3 there is ultimately less burnt oil passing through the cat.
 
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