Marvel Mystery Oil

[Fitz98]

I have a 98 Expedition 5.4 4x4 with 188K miles on it.
I have been trying to get to the bottom of an oil burning condition, but can't quite seem to get there. It is not bad enough to show any smoke out the exhaust, no visible oil leaks, pcv tests good, but bad enough that I have to keep adding oil every 500 to 1K miles.
The general concensus is that it is likely valve seals or rings, and if it was either one of those, the job would cost close to the value of my truck. On one thread, there was a post about the oil rings on pistons sometimes gets stuck.
I am curious if there would be any advantage or harm to adding some Marvel Mystery Oil to see if there is any potential for improvement, without rebuilding the top and/or bottom end, or would I just be wasting my time?

 

[buck91]

I'd put my money on the valve stem oil seals. I've done it on a couple 4.6L mods, not bad at all just takes time. As long as you remove enough "stuff" to get the valve covers off, you can leave the cams in as they make a special spring compressor for this. Its pretty cheap, I picked one up years ago for maybe $30.

That '98 should be an NPI 5.4L, right? Although the earlier 4.6L engine with the F1AE head castings were TERRIBLE for burning oil via the valve stem seals the F5AE castings revised this issue and are not nearly as problematic- but still pretty common. I haven't heard of many PI engines with this problem (99+ windsors and 01+ romeos, except the superduty 5.4L was NPI in 99) but I wouldn't be the least suprised to see this issue in ANY mod motor.

 

[OVERKILL]

If it was valve seals you'd have visible smoke on start-up. If it was rings you'd have visible smoke under hard acceleration.

MMO isn't going to do a thing IMHO. You've done the revised PCV kit? Was there oil in the old hose assembly? Is there oil in the throttle body or intake? Might want to take a gander at that before pursuing this further.

 

[expat]

The short story.
I bought an 84 Toyota pick up that had been stored 20 years.
I had some oil consumption and ruff idle during the first 2 years of my ownership, until I tried half a quart of
MMO during winter.
Idle smoothed within 200 miles, consumption since has been negligible during 5k oci's.

This has been the only time I have used MMO, I see no reason to use it on a regular basis. But in some applications it can work, it's cheap and is not likely to do any harm.

 

[leroyd92]

i like mmo or tcw3 for things like this.


my ex gfs suzuki reno smoked on startup. did it if the car sat for more then 2 hrs. she filled the tank and i added 2 oz tcw3 per 5 ga along with 1 qt of mmo in the crank case. drove over an hr on the highway with the car out of overdrive. 3rd or whatever it was ( 32/3500 rpm ) and it never smoked again... we drove out of town to go have dinner and the next morning it didnt puff any color out the pipe...

at this point, you have nothing to loose... if i were in the same situation, id use a super thin synthetic oil and go heavy on mmo/tcw3 in the fuel. drive it for a while out of overdrive and see what happens. my 5.4 only has 100k

 

[crazyoildude]

What oil weight are you using? Around 10 years ago at an engine rebuilding seminar there was a tech ( i don't remember where he was from) that said 5w20 was an absolute must for those engines because the 5w20 will lube the valves better than a heavier oil.. He could be correct but to this date i have no solid evidence of that and i sometimes run a syn 5w30 in the summer in one of my 4.6 fords

 

[bvance554]

Originally Posted By: OVERKILL
If it was valve seals you'd have visible smoke on start-up. If it was rings you'd have visible smoke under hard acceleration.


Neither is true these days. I've had a couple oil burners none of them smoked at any point. That was a simple diagnosis that worked years ago, but most of any oil gets burnt up by on of a few catalysts before it ever exits the tailpipe as blue smoke.

If it were my vehicle i would monitor it, and add oil as needed. I don't think MMO would do any harm, but I'm not sure I'd do it either.

 

[901Memphis]

Use a high mileage oil and keep it in the safe zone, with the amount your spending on gas an extra $5 a quart isn't going to kill you to keep it topped up. I wouldn't even worry about it at that age.

 

[OVERKILL]

Originally Posted By: bvance554
Originally Posted By: OVERKILL
If it was valve seals you'd have visible smoke on start-up. If it was rings you'd have visible smoke under hard acceleration.


Neither is true these days. I've had a couple oil burners none of them smoked at any point. That was a simple diagnosis that worked years ago, but most of any oil gets burnt up by on of a few catalysts before it ever exits the tailpipe as blue smoke.

If it were my vehicle i would monitor it, and add oil as needed. I don't think MMO would do any harm, but I'm not sure I'd do it either.



Before the cats light (first start) a valve seal problem will smoke. I've seen it on many a modern vehicle, so it is certainly still true. Under acceleration, well, it is going to depend on how healthy your cats are and how much oil you are burning. My M5 lightly "fogs" under hard acceleration (it only has two large cats) but that's gas smoke from the rich WOT tune it has from the factory. I've seen this a lot with forced induction vehicles as well, which are tuned rich.

He's burning a LOT of oil (a quart per 500 miles). If it was valve seals, it would smoke on start and take-off IMHO. I've seen it with a few CV's with similar consumption, which have very similar exhaust and the same engine family. I've never seen a CV with baffed oil control rings, so I can't give an example of that one unfortunately.

 

[Fitz98]

Originally Posted By: 901Memphis
Use a high mileage oil and keep it in the safe zone, with the amount your spending on gas an extra $5 a quart isn't going to kill you to keep it topped up. I wouldn't even worry about it at that age.


Funny, that's what my mechanic says, almost exactly. He said it will run good and won't give me any troubles as long as I keep it topped off. With that being said, I am of the mentality that there is a reason, a cause and a solution, so why not fix it, as long as it doesn't break the bank and cost more than the value of the vehicle. At this point, I may just have to wait a little longer, until more symptoms present to help with the diagnosois.

 

[badtlc]

The value of your current vehicle should never factor in when considering a repair. The value of the vehicle you would buy in place of your current vehicle if you got rid of it is the value you'd want to consider.

 

[jk_636]

Just try a bottle of MMO and see what happens. You may be surprise what happens. It has worked wonders for me in the past. I am a firm believer in the mystery oil.

 

[SteveSRT8]

Originally Posted By: jk_636
Just try a bottle of MMO and see what happens. You may be surprise what happens. It has worked wonders for me in the past. I am a firm believer in the mystery oil.


And of course the caveat is it is unlikely to hurt much of anything. The stuff has been in my garage for over 40 years, it has its place for sure...