Used engine flush, now rear main seal leaking.

[Rayyy]

Wondering if someone can shed some light…

I used a can of Liqui Moly engine flush before an oil change, the oil came out goopy and super black, so it seems like it did clean out gunk/sludge from the engine.

However, now my rear main seal is dripping big time, and I’ve read disclaimers that engine flush treatments can damage the seals??

Is the dripping temporary? Or is my seal actually damaged?

Anything I can do to at this point?

 

[MassHoe04]

I don't know, but my Jeep 4.0 had been running traditional dinosaur oil it's whole life and was not certain how well it was cared for in terms of oil changes. I never leaked a drop.

I am thinking all the deposits that were allowed to build up might have actually been helping to keep all the oil in where it belonged.

I figured if it wasn't leaking and was running great on regular old 10W-30, I didn't dare try the old "just run some auto tranny fluid before you dump the oil..." trick or engine flushes of any kind.
Maybe those methods are perfectly safe, but I was scared sh1tlesss to even think of trying any things like that.

I did not leak. Others had. Coincidence? Maybe...

Sorry you had that happen. I can't explain for you what happened, but maybe there is something to the idea of not trying to get old engines free of deposits and squeaky clean.
As seals wear, maybe it is possible the buildup pf sludge and deposits help fill the gaps. ??

Only theory, so don't beat me up too bad.

Anyway, my 04 Tahoe hit 212K, runs 5w-30 (whatever is on sale). Maybe it weeps tiny bits here or there, but not enough to drip on the driveway. No flushes for me. Just frequent oil and filter changes. I don't always hit the target, but I shoo for every 3k miles to the extent possible.

 

[Alex_M]

The flush did not damage the seal, but it did uncover that it was worn. I am personally anti engine flush. Breaking free stuck on gunk that is not currently causing any issues can have no good come from it. At best, parts you will never see "look" cleaner. At worst, you uncover seal issues like yours or you knock loose chunks or particulates which are now suspended in your oil running thru your engine instead of being stuck in one place not doing any harm. Oil filter hopefully catches most of those, but they are still running thru your oil pump first wearing the pump.

Do your next couple oil changes in short intervals to get as much of the newly suspended contaminants out, use high quality filters. Mobil or Wix XP.

Your rear main is probably just going to leak now. If you use synthetic oil, switch to conventional - sometimes helps.

Sludge and gunk, once it exists, is best being left where it's at.

 

[OR VietVet]

What @MassHoe04 and @Alex_M said. You had seal(s) that was already worn and deposits blocking some leakage and now the cleaned surfaces are letting the oil flow. This happens way more with "dino" oil than synthetic.

 

[nonickatall]

With oil pan gaskets, it sometimes helps to simply tighten the screws a little. Of course, be careful not to overdo the torque and destroy the threads.
Otherwise changing the oil pan gasket is no magic and the O-ring of the oil pump pipe can be changed directly in the process, which is a weak point in the engines.

 

[BMPNUGLS]

I’ve always been one to maintain low mileage oil changes and stick with the same type oil (full synthetic for recent vehicles) with not many additives used - with the exception of some Marvel Mystery Oil in crankcase and gas tank once every other oil change…seems to work well.

BUT, I’ve seen many people swear the below additive really works to revive old seals, gaskets, etc and stop or minimize leaks…might give it a try before looking at replacing the rear main seal.

ATP Automotive AT-205 Re-Seal Stops Leaks, 8 Ounce Bottle https://a.co/d/hzTbrZu

 

[Sam Harris]

I’ve always been one to maintain low mileage oil changes and stick with the same type oil (full synthetic for recent vehicles) with not many additives used - with the exception of some Marvel Mystery Oil in crankcase and gas tank once every other oil change…seems to work well.

BUT, I’ve seen many people swear the below additive really works to revive old seals, gaskets, etc and stop or minimize leaks…might give it a try before looking at replacing the rear main seal.

ATP Automotive AT-205 Re-Seal Stops Leaks, 8 Ounce Bottle https://a.co/d/hzTbrZu

I’ve heard this as well, but don’t have any experience with it. Although I do have a bottle on the shelf. Lol. Interested to hear any thoughts on it. Also, adding more if it than directed definitely causes problems. I watched a video of a trans tear down where all the seals were swelled up, causing massive problems, due to adding a lot of this type stuff.

 

[nonickatall]

I’ve heard this as well, but don’t have any experience with it. Although I do have a bottle on the shelf. Lol. Interested to hear any thoughts on it. Also, adding more if it than directed definitely causes problems. I watched a video of a trans tear down where all the seals were swelled up, causing massive problems, due to adding a lot of this type stuff.

I would never pour something like that in my engine. What closes leaks, also closes oil channels and orifice. Oil leaks are way too versatile. Torn seals, improperly tightened oil pans, worn oil seals.

But even worse is cooler tight. Anyone who has ever taken apart an engine with stuff like that in it, would never pour something like that into their engine.

And never ever put something like this in an automatic transmission.

 

[Sam Harris]

I would never pour something like that in my engine. What closes leaks, also closes oil channels and orifice. Oil leaks are way too versatile. Torn seals, improperly tightened oil pans, worn oil seals.

But even worse is cooler tight. Anyone who has ever taken apart an engine with stuff like that in it, would never pour something like that into their engine.

And never ever put something like this in an automatic transmission.

This was my line of thinking.. which is why I never used it, and it sits on a shelf. (After I bought it of course..) Maybe it will be good to help start a bonfire.

 

[OR VietVet]

I actually saw adding brake fluid to engine oil, swell up a rear main seal on a Ford van and get us home from the Lake of the Ozarks. It was pouring out more than I had seen before and I saw the leak slow way down and get us home. Amazed me.