I have written about this before but I now have a good bit of experience about using a quart of MMO in each oil change. I have read where MMO is a good, slow engine cleaner when added to the oil change. (Slow enough not to clog up the oil pump) I have a 2000 limited with the 3.4L 5VZFE engine. I have always run Mobil 1 and the past three oil changes, I have replaced one quart with MMO. I ran the first oil change with MMO about 3000 miles and the oil was really dirty. During my run on the 2nd oil change, I seemed to notice a smoother engine idle, slightly better mileage (about 1 - 2 miles more per gallon but this could be due to the change over from winter fuel formula to summer fuel formula at the gas station) and when I drained the 2nd "batch" the oil was still pretty dirty with about 4,000 miles on it. I did however, wipe some on a white piece of paper along side of the 1st MMO "batch" that I had saved. It appears a bit cleaner. Now I am on the 3rd go around with the quart of MMO and it might be my imagination, but my engine runs smoother and I seem to have better power right off the line. It took me a LONG TIME to decide whether or not I was going to try MMO in my engine. However, I am glad I did. I can tell a difference and as I intend to keep my T4R until the wheels fall off, I am careful about what I put in the engine.

People tend to call MMO "snake oil". I have used it in an older engine to help with a lifter tick during the cold months and it did help. I got the idea from my uncle, who worked for some time in Canada, where his boss told him to run it during the winter to help the oil pressure build up faster. But the thinnest grade of oil back then for him was 5w-30 (early 1990s).

I don't see any harm using it in moderation. I would think though that your Mobil 1 synthetic oil has more than enough additives in it to slowly clean the 5vz thoroughly and you don't need the MMO as a cleaner.

Let us know how it keeps working for you.

http://www.talensmarine.com/msds/Marvil%20Mystery.pdf

anybody remember this stuff, gotta admit I used to buy all these things (40 years ago):

http://barsproducts.com/catalog/view...reatment-100qr

http://www.stp.com/products/oil-addi...oil-treatment/

Has Mobil 1 been used from the start? I do think that the Mobil 1 has also been cleaning as well. I switched to pennzoil ultra and I've noticed my 5VZ to sound smoother but it may just be my imagination. I have my doubts about all these oil additives since the oil wasn't designed to be mixed with anything.

I understand the sentiment about MMO being "snake oil" and that was the reason I took such a long time before I decided to try it. I have to say, I am glad I did. Mobil 1 is certainly the best fully synthetic around that is widely available and having lived in Norway in brutally cold temps, I know the capabilities of it. Amsoil is just too pricey for me and its hard to find around here. Back to the MMO; I looked over their website and searched the internet for a really long time before I decided to give it a go. A company whose product has been along as this stuff (originally used in radial aircraft engines) has to be making something worthwhile. A buddy of mine used it in an old farm truck that sat for years and he said he poured it in, let it sit overnight and after a few tries, it cranked right up. I will keep everyone posted on my experience with it.

Just changed my oil again and replaced one quart of oil with MMO. My truck has never run better than it has when I use MMO and NO - I do not work for the company that makes this stuff. A buddy of mine commented on how well my truck ran while we were driving around yesterday... Soon my rig will have 200K on the odometer and at this rate, she will easily get in another 200K more.

When I got my second truck it had 216k miles. I got the records but wanted to start fresh for myself and peace of mind. I did one treatment of MMO and afterwards it did idle smoother. Ive been doing it once a year for good measure. Snake oil maybe but Im a believer.

Good luck

I researched it quite a bit the last week and I did the same last evening!

Yes it is smoother and has more pep to it. I am also adding 8 ounces to my fuel tank during fill up(20 gallons)!

I will report back on how it performs as time goes. The oil I used is Castrol 5w-30 Magnatec Synthetic Blend.

For those wondering why I did this... I usually get my Oil changed at the dealer and specify that I want synthetic whatever brand he carries. Usually Pennzoil or Mobil. But the last time I think he put one of his Junk/Bulk oil instead of synthetic. I didn't know.

So I usually change oil every 7000 miles with full synthetic and it is fine as the oil doesn't go really black.

But since he put junk oil in there and I was too busy last year I put off my oil change at 7000 miles and my engine gunked up pretty bad. Finally when I got around to taking care of the vehicle, I Immediately went to an oil service place and changed it with Castrol... drove it for 500 miles and then added half a can of seafoam in the crankcase. Drove it for another 40 miles, came home and drained the oil. Blobs of gooey oil and one even had a round shape with a hole in the middle!!! The gunk must have stuck to some bearing or something...

Only then I noticed that the dealer when changing oil, never really removed the old gasket from the drain pan nut and kept building a pyramid of washers one over the other with every oil change and then on top of it torqued it so bad that the oil pan hole went inside a little. I guess he was trying to stop the leak with a pyramid of washers!!! Morons!!! They couldn't spend a few seconds to remove the old washer.

So I said, never again and bought me some ramps and I do the oil change myself. Had to remove all the stuck washers with a knife and got a nice felpro washer and now its good.

I knew I had lot of sludge in the engine. So I changed to Castrol again myself in the home. Drove it for 3000 miles and then finally yesterday during oil change took the plunge to add half a quart of MMO along with my Oil. Engine is smoother and more pep.. I am planning to send a sample of the mixed oil to Blackstone to see if it altered the viscosity badly or just a little. If it's just a little I plan on using it with every oil change. Toyota recommends 5-20 now anyway so with 5-30 hopefully it didn't thin it too much!

I thought I had a pretty good handle on how internal combustion engines work, but maybe I don't. I'm trying to figure out how the heck adding an oil supplement would make an engine have more "pep". Maybe thinning the oil and making it flow easier would have an effect, but modern synthetic oil is almost as thin as water and flows pretty darn good all by itself. Maybe the cleaning agent in the additive could make hydraulic valve lifters work better, but the 5VZ has solid lifters. Does the oil additive somehow increase compression? Please educate me!!

It could also be that I just changed the oil?

As I said, I have to monitor how it performs in the long run.

My goal was NOT to increase performance, but to just clean the engine of sludge.

But adding the oil to the fuel, apparently helps the lifters as it lubricates it. Unlike seafoam, MMO is mostly mineral oil with other additives.

Pretty sure it operates on the same principle as K&N intakes and TRD stickers.

I forgot to mention I had a ticking noise from the right side of the engine that is completely gone.

As for the pep, I guess the rings must have been stuck with sludge before and now is free. Just a guess..

Another main reason I did this is have the VSC Track lights on. So I removed and inspected the Oil Control Valves and one was pretty dry and subjected to heat(before I changed the oil the first time).

I replaced the OCV's and after a few hours the lights are still on. Next step is to change the crankshaft sensor. But hoping MMO will dissolve any goo on the sensor and get it working again.

I have a comm error with the ECU, not sure if it's the ECU or the crankshaft sensor gone bad. I intend to replace that as well this weekend and see if that works.

if not, then that's another story for another day.

So MMO was to see if it will clean the engine that could solve a lot of my problems.

My wife had a 01 Celica. The engine started making noise and our mechanic told us that the engine was know for oil starve issues and was most likely on it way out. He advised instead of throwing money at the Celica to run MMO for about 1000 miles, then drive it to the dealer and trade it in. It calmed down the noise and she traded it in on a new Jetta TDI. Now we are waiting to hear what is going to happen with the dirty TDI. I am hoping I can get her back in a Toyota, but man does she like that Jetta.

Yes, this.

How the heck can an oil change make it feel "peppier" or "smoother".
In my day the performance trick was Thrush Muffler stickers.

That is exactly what an oil change does!!!

And, I am talking about it relatively compared to the gunk/junk/bulk oil the dealer had put it.

If you have a fine engine with no issues, then MMO is not magic oil to get more performance or smoothness.

I am using it to (dis)solve a problem.

Why is that so hard to understand?