My father used Marvel Mystery Oil ---MMO--- since it came out in 1922 or 23, we use it 10% in the cranckcases of trucks, cars, inboard boats, I/Os, you name it.
add 4oz per 10 gal of fuel and it keeps the injectors clean and stops deposits int eh fuel system.
when my brothers and I went to war he sent us MMO! and we cleaned and lubed our M14s with it and later I used it on the M16 A 1 with great effect.
MMO helps high mileage engines, new engines, new boats, bikes, atvs you name it AND it acts as a fuel stabilizer too for winter storage.
Read the instructions on the can. If you suspect your engine is sludged, then I suggest you do a quick oil change after adding the MMO, like a few hundred miles at most. If you're right, and the MMO breaks up the sludge, it could also block the oil pump pickup, causing severe engine damage. So changing the oil soon after will allow you to inspect for any solids, and adjust your maintenance schedule appropriately.
I think Auto-RX has some form of MMO in the formulation. I'm not 100% but I'd bet. It's been FOREVER since I heard anyone speak of MMO. Now a days, I just run 100% synthetic oil, even on my high mileage vehicles. Synthetics are the REAL deal.
I heard the stories about RP having some problems. They were selling a pure racing only oil to people to run on the street that didn't have proper additives for everyday use. I heard about this on a Dodge forum I subscribe too for my Durango. At least with Amsoil, they offer a full warranty against any defects found to have been caused by the engine oil.
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