Delta11
Member
I started using MMO in my 2010 Ram Longhorn 2500 5.7 when I bought it with 95k on it. It was and is the nicest truck that I have owned. Anyway... with plans to keep it Long Term got me interested in MMO. Started by adding it to my first three or four oil changes of which I did in approximately one month in order to clean the engine. The last oil change the oil was clean so I figured that I had done some good. Since then I have added one quart to the oil change every 5000 miles. I have 230k on it now. I tried synthetic once and It Seemed like the engine shook on startup and ran rough until it warmed up so I immediately drained it out and went back to full Dino oil as they say 5w20. Thought about going heavier with 5w30 since the MMO has a thinning effect but I felt that was what MMO was about so I stayed with 5w20. So I started adding it to the gas hoping for the benefits of upper cylinder lubrication and extending the life of my engine of course. Yes I thought that it would be equivalent to putting Diesel into a gas engine but at 4 ounces per 10 gallons it was going to be a wash or may help long term. I had the transmission changed at 195k, rear wheel bearings, And O2 sensors since they had it up in the air. Months later the engine codes started popping up 071,072,0420 and a couple of others I forgot exactly, one said pre cat 0397 maybe and a misfire code but did not state the cylinder. Put some cat cleaner in my tank and B12 to try and clean it up. Codes changed after that...some cleared some stayed and some new ones. I had them all written down but I trashed it. Anyway I looked up all of the possibilities on the internet that could bring them in. Changed the MAP sensor and it seemed to help at first, caused my mileage to increase up to 17.2 at 70 mpg which has never happened but that was short lived and I don't know why yet. To end this story I changed the plugs which were fouled and the O2 sensors before the Cat...one had stopped putting out voltage according to my scanner. Cleaned the two after the cat with Electrical cleaner since they all were new and reading voltage. All of the injectors and coil packs tested good. So I believe that the MMO in the gas fouled the plugs in return fouled the O2 sensors and threw up the cat code because of the unburned gas/mmo which fouled the Cat somewhat. What I did cleared the codes and all is well. I have new coil packs on the way since I am keeping this truck as long as possible...It has a dip stick on the Transmission Right! My opinion...Don't put Marvel Mystery Oil in your gas tank even at the recommended 4 Ounces per 10 gallons.