posted this over in the 2nd gen forum... have a look if your interested... talks about MMO in a 3.9 Dak...

https://dodgeforum.com/m_615141/mpag.../tm.htm#615141

 

What's the viscosity of MMO? You can run into problems with warranty claims if you're running oil outside that which DC specs.

 

I dont know about viscosity... this stuff is pretty thin and I think it's more of a cleaner than anything else. I had a lifter ticking on my 2000 and put in about 12 oz of the stuff and the tick was gone right after the following startup. Of course there was no dealer warranty on my 5.9 as I am my own warranty station...

 

I've still got ~30k on my extended warranty, and I intend to keep it that way. So for me, I'm using mobil 1 at 3-4k intervals until I hit 100k, which should be in about another year and a half.

 

Marvel Mystery Oil is AWESOME!

If you have any doubt about the stuff, let me show you my 16 y.o. Mercedes with 200K+ miles on it!

I substitute a quart of oil for MMO in every oil change on that car. You can also use it in the fuel tank to clean out the system.

 

welcome to df...

you missed the thread about my daughters '93 honda going from 23~25 mpg consistantly to 29~31 mpg consistantly. all after adding 1 quart in place of a quart of dino oil. she is so happy its un-real.

 

just buy one of these new throttle body spacers, it would essentially double your gas mileage
https://dodgeforum.com/m_607114/tm.htm