Home Forums Hunting & Shooting Hunter's Campfire possible sludge in engine - Marvel Mystery Oil

I'm not certain I have any sludge, I don't think so with the car, maintenance history and mileage but I'm getting intermittent low oil warnings on my car whenever brake hard, occasionally it just happens while driving as well.

I always check the oil and I'm never low. I have replaced the oil sending unit twice over the last 18 months or so and that doesn't fix the problem. I had an old ratty Galant with 200K miles and the low oil light would come on at idle. I ended up putting in 10W-40 and that "thicker" oil seem to solve the problem - at least with the oil light coming on. But this isn't a repeatable thing. It happens for a few days then goes away for 2 months then starts up again.

I'm thinking that maybe I have some low level sludge build up? It may very well be an electrical gremlin but short of tracing wires I've done the obvious.

If there was a "shortcut" to addressing sludge, I was thinking that maybe adding marvel mystery oil to the crankcase, running the car a bit and then flushing it with two oil changes might be a way to clean it out.

I've always changed the oil with synthetic every 3000 miles and I am at 136K miles now.

I don't know if it will help - I just want opinions on whether it will hurt anything.

My dad used to always run about a 1/2 to 3/4 pint of diesel fuel in his motors for a few minutes before he changed his oil. Help or not?, it never seemed to hurt them.

Only thing about "flushing " an engine is the better
than average chance of breaking loose all the built
up sludge, only to have it severely clog the oil
pickup screen, then you are truly screwed.
Used to be when vehicles had a screen and a
sump that the screen poked down into, you could
drain the oil and refill it with a about a gallon or
two of solvent or naphtha and let it sit and soak
for a couple of days, and it would melt a lot of
the sludge and you could take the plug out and
drain it and pour more stuff through with the plug
out and the remnants would rinse on out.
I'm not sure at all about the modern OHC engines
because of their complicated oiling systems.
Not all all like an old V8 engine
Good Luck

Could be the sending unit.


https://www.lowes.com/pd/Lucas-Oil-...QQ0AEAQYBSABEgKJ0fD_BwE&gclsrc=aw.ds

What kind of vehicle? I saw a youtube video where a mechanic pointed out on a 2006 or so 5.3 Chevy that the seal on the oil pick up tube can get hard and not seal properly causing a drop in oil pressure.
3000 mile oil changes seems a little early and kind of expensive. I sold my 2000 F250 with 220,000 miles and it was on a 5-7000 mile syn blend schedule. The guy driving it now is a friend and is really happy with it.

What I would guess

What are you driving ?

Variable valve timing ?

I had a 99 4cyl Camry and a TOyota Avalon 6cyl of the same year brought new. They purportedly had serious sludge issues(I know it was a Toyota:)) . I used mobil 1 on both vehicles and had valve covers removed one at 75 k and the other at 200 k and there was hardly any sign of oil residue buildup in both engines.

2007 Acura MDX 3.7L

I guess it could be the sending unit, that would be the general culprit, but its either shorting out the ones I replace it with or I got 2 bad ones in a row because I have put 2 on it in less than 2 years.

What kind of vehicle? Is it a low Pressure light or a low Level light? My old Buick had both. If the oil got over a quart low, the low level light would come on and I knew it was time to add a quart.

Jerry

its an oil level warning - comes up thru the dash and on the navigation display unit

It sounds like it could be the oil pick up tube on the oil pump. If the oil isn't low, and you have changed out 2 different sending units, I would think you could rule out the sending unit. Could be the gauge also?
It isn't unheard of to have the pickup get loose from the pump. Some are just crimped on.


Clyde

so that would mean dropping the oil pan. That wouldn't be that big of a deal to do. Probably give me a good idea of what is going on in the engine.

..........................Well to begin with, if you have been running synthetic oil and on top of that been changing that oil every 3,000 miles then you certainly should not have any engine sludge problems whatsoever. One of the main reasons why synthetic oils should be used is because they do not have the petroleum based acidities and other more harmful properties that regular non synthetic motor oils have and synthetics do not break down nearly as quick as non synthetic oils. Since you have been using a synthetic oil and another reason for using synthetics, is that there is no need for any oil additives. Oil additives imo treat the problems that non synthetic oils create. So in your case adding Marvel Mystery oil imo would not change anything nor improve anything.....Imho you have an electrical problem of some sort, possibly an electrical short or possibly a defective gauge that is causing your intermittent problem when braking hard. As long as your oil level is ok, are not leaking any oil or have no oil burning internal issues then you'll be fine. You might want to take your vehicle to an auto electrical shop to trace down any possible shorts which could be a bad wire or a bad connection of some kind.

I can't see you having any sludge with that regime and I certainly wouldn't do something like that Marvel Mystery Oil routine. I'd look for another cause.

having the same engine in 2 different vehicles.... its definitely an electrical issue....

if you aren't needing to add any oil, when it says you are a quart low...

I change the oil on those two engines I have, one every 10k ( the Acura RL ) and on the Honda Pilot every 20k, with a filter change ever 10 K.

running Mobil 1 on both engines... last time on the valve adjustment, no varnish or sludge on the upper valves & head. 310K on that engine.

engine uses a quart on the Honda ever 5K or so... so I wouldn't worry about the " oil issue" too much...

I concur...

Hard to believe 3k oil changes with synthetic would EVER build sludge.

If you pull the sending unit... bench test it. If you still have the old ones... bench test them as well.



Excellent point. Pickup, gauge, wire, ground all potential suspects

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Check your owners manual... use the thinnest oil in the winter... always better to potentially burn a little that fight thickness.

We got a 1998 Isuzu a month or two back... don't quote me, but I think the owners manual recommended oil from 5w-20 to 20w-50... WTF?

Might it be that the sending unit you have been changing is a pressure sending unit and the warning you are getting is for low oil LEVEL?

Is there another sending unit for the oil level?

Better there - done that - ruined an engine.