Marvel Mystery Oil or what?

[91Pioneer]

Something I've been thinking about lately. When I bought my truck last year, the PO didn't do really any maintenance at all. He had it about 9 years (friend of a relative, good chap but not a car guy).

 

So I put in new oil and a filter. I strongly suspect he did not have the oil changed for at least 3 years, more than likely it was older than that. Long story short the oil was blacker than hell and I'm pretty sure the oil filter was in bypass mode.

 

Anyway I've put a few thousand km on it now with fresh oil & filter but I'm still thinking maybe I should put an additive in the oil to help clean things up.

 

I'm seeing some posts on Marvel Mystery Oil (MMO). If I was to add say a half quart now and change the oil again in a month does that sound like a good plan? I think the oil is in pretty good shape but I can just imagine there is crud in the engine.

 

Also, is it safe to run the truck daily (and during winter) with 5 quarts regular oil plus 1 quart MMO? I have the oil already to do another oil change, just thinking about my options.

 

Background, I recently swapped gauge clusters so I actually know what's going on with my oil pressure now. At startup and for the first few blocks the oil pressure is pegged high, but after that it is totally normal (I compared the specs to what the owners manual says).

[91Pioneer]

One other question, is MMO any better than Seafoam in the oil? I've used Seafoam in a car or two in the past (in the oil, gas tank, and vacuum line)

[Marine1Texas]

Marvel will be fine.

 

after ever summer we do a cleaning out of oil on our farm trucks. We change oil and put in 50% 30 weight and 50% auto trans, run it for about 15 minutes at 2 grand. we drain it out and then put new synthetic 10W50. Our trucks always have clean oil, and never have leaky gaskets or seals. We put 300K on this old 4.0 and when we took it out to do a 4.0 HO head swap it was super clean. Some may not like my method, however results show for them selves. I do the same for my diesels too.

[FrankTheDog]

I have run 1qt MMO with 5 qts oil. No harm done that i can tell.

It did get a little quieter.

[ScottJeep]

JMHO but the SeaFoam might be much more aggressive than the gradual and GENTLY cleaning that will be best long term. 

 

My most recent XJ was a mess internally.  

 

When I finally yanked the head due to a burnt #2 exhaust valve ( part swapping lesson LEARNED ) 

the inside of that motor was a mess.  I had been using MMO...IF I had used SF I think instead of the pickup being sorta blocked

it would have gotten totally blocked and the engine and it would have been toast. 

 

Now with my head job I replaced MANY other internals. But that was over two years ago. The power the engine still had was impressive,

it indeed helped sell the Jeep, and I still see it from time to time around town. 

[cruiser54]

MMO works great for your scenario. Monitor the progress by shining a light into the oil filler hole. 

[Crash]

I use MMO all the time,at oil changes. I use seafoam or Berryman's B-12 (which is basically the same but cheaper) in the crankcase about once a year for a week or 50-100 miles before I do an oil change. Since it is a solvent of sorts, I personally do not recommend running it for an extended period of time. But there are some old timers that swear by it. 

I also use it in the intake, and fuel tank. 

I always keep at least a quart of MMO in my vehicles. It can be used for most anything requiring some type of oil. 

[91Pioneer]

Well I'm sure I saw MMO locally but I went to Walmart and Canadian Tire tonight and they didn't have it. So in the end I bought Rislone and put that in. It has really good reviews. Maybe I'll put a little Seafoam in the gas tank just for giggles (I did that when I bought the truck).