MMO made my rear main seal leak!

[Chris142]

I doubt it really. Must be a strange coincidence though. I put 16oz of MMO in my 4.0 Jeep engine last Wednesday. Friday @ lunch time I noticed a silver dollar size leak on the ground under it.

It's coming out between the bell housing and the dust cover.


It has never leaked till now.

Today I drained it and put Maxlife in it. I'll keep ya'll posted as to weather or not it stops leaking.

 

[c3po]

I know this may sound dumb, but why did you put MMO in there, how many miles do you have on your Jeep.

 

[Chris142]

77,000. It gets a noisey lifter ocasionally so I put the MMO in there to see what happens. I only put in 1/2 the recomended amount.

The noisey lifter is quiet again.

 

[Craftsman]

I guess MMO did it's job.

 

[rg200amp]

MMO is a strong cleaner. I have used it my my F250 with the 6.8L V10. I would drain a quart, and replace it with a quart of MMO about 500-700 miles before an oil change.

CRAZY how dark the oil got!!

the oil was golden when i draind the quart, then 500 miles later with MMO, the oil used to be black and gritty.


I have not, and would not use MMO in my car now. I would reserve MMO for a motor that has light sludge

 

[demarpaint]

I've used it for years in the oil and the gas with good results. Many years ago I would run a full qt for the entire OCI, but stopped doing that in the late 70's, not sure why. I've been using it now, 16oz for the last 500 or so miles of the OCI without issue. I am currently using A-RX so I stopped using MMO, but continue to use it in the gas.

It might have cleaned up dirt that was stopping the car you're referring to from leaking. I would try a HM oil with the seal conditioners in it, I bet it will stop leaking. As far as cleaning up lifters the MMO works great.

Frank D

 

[Chris142]

I put 350 miles on the jeep yesterday with the Max life oil in it. The leak has slowed to just a wet spot on the bottom of the bell housing.

 

[demarpaint]

That sounds good, it might just stop, or slow it to a point where its not an issue. Give it some time.

Frank D

 

[Donald]

Get rid of the MMO and use Auto-Rx.

I see only one use of MMO, water got into the cylinder and its now rusted. In that case squirt some down each spark plug hole and let it sit for a day or so.

 

[Chris142]

Well after about 650 miles the leak has returned. It's leaving a spray on the transmission crossmember and a silver dollar size drop everywhere I park it.

Replacing the rear seal in this is a pretty big job. The exhaust comes off the engine then crosses over to the other side directly under the pan. Thats gotta come off before the pan will come off..


Not looking forward to this.

 

[Brett Miller]

MMO made my stool softer.........

 

[demarpaint]

Before you start tearing it apart why not get the MMO out? It probably did a nice job cleaning up things that might have been slowing or stopping the leak. I'd try either A-Rx, a HM oil, something for stopping oil leaks that has seal conditioners and swells seals.

Some people who post here had good results with engine oil stop leak products, as well as A-Rx for leaks. I wouldn't looking forward to changing that seal either.

Frank D

 

[Frank]

You don,t want to swell seals (you weaken seal material) Auto-Rx unit it will clean seal matrial (front & back) making seal very pliable (will initially leak more) go to Castrol GTX type oil simple additive package will restore pliability . Leak wil stop.

 

[02zx9r]

i have heard that mmo in the oil will thin it out pretty good. I only use 4 ounces of mmo in my tank every tank or every other one

 

[Chris142]

Originally Posted By: demarpaint
Before you start tearing it apart why not get the MMO out? It probably did a nice job cleaning up things that might have been slowing or stopping the leak. I'd try either A-Rx, a HM oil, something for stopping oil leaks that has seal conditioners and swells seals.



I posted on the 5th that I had drained it and put max life in it. it's the max life thats now leaking all over.

 

[Gary Allan]

Well, Chris, at least it's a two piece seal. I wouldn't want to wrestle the trans and t-case to replace a one piece. Mine has weeped from very early in life. No puddling or even a splattering on the trans ..but always a drop waiting to gain enough mass to drip.

 

[Rick20]

My 2 cents: Likely that MMO did some cleaning, but thinned the oil out somewhat. Also MMO did not slowly dissolve deposits and might have ended up lodging particulate matter under the lip of the seal. Maxlife is supposed to swell seals, at least from what the TV commercials would lead you to believe although valve stem seals are always pictured in the adds. This combo is adversarial in attempting to solve the leak.

If it were me, I would run a clean dose of ARX in a simple dino(conventional oil) to clean up the crank journal and mating seal.
Then run a simple mineral oil (dino) rinse to shrink and stiffen the rear seal to reconform to the rotating journal of the crank.

I would say this has a good chance for success for 20 bucks. Otherwise, as Gary has mentioned at least its a two piece seal.

 

[c3po]

Chris142, I used Auto-Rx on my 1983 Chevrolet El Camino and my Mom's 1998 Chevrolet Monte Carlo with great results.

On both cars it stopped the rear main seal leak. You have a few problems here:

1) You have crud around the seals
2) This crud is probably making the seals hard
3) You need to get rid of the crud
4) You need to make the seals pliable

The good news is that Auto-Rx with some cheap dino oil can get rid of all of your problems.

MMO is old school as well as this high mileage oil that just swells the seals, Auto-Rx will take care of your seals unless they are ripped or torn.

I have 364,000 miles on the El Camino and I just use cheap Wal-Mart Super Tech Dino Oil, and no leaks. When I used Amsoil 100% Synthetic after the clean and rinse I had leaks, Amsoil 100% Synthetic is a great oil but my seals just did not like it.

I would follow what Frank says and you will be fine or PM me and I will help you out.

 

[demarpaint]

Originally Posted By: Chris142
Originally Posted By: demarpaint
Before you start tearing it apart why not get the MMO out? It probably did a nice job cleaning up things that might have been slowing or stopping the leak. I'd try either A-Rx, a HM oil, something for stopping oil leaks that has seal conditioners and swells seals.



I posted on the 5th that I had drained it and put max life in it. it's the max life thats now leaking all over.


Got it, might take some time for the leaks to stop/slow down, no matter what you use. MMO is a 5W oil so it probably thinned things out pretty good. At this point Rick20's advice might be in order.

Frank D

 

[Steelhead]

chris,
run a 15w40 such as Delo 400 to slow the leak down until your RX treatment is complete.

jeep 4L thrives on 40 weight especially in mild Cali. wx.