BLUF: Recently replaced my rear main seal and after start-up it DUMPED oil from there.


Background: During the rebuild of my transmission, I did some preventative maintenance. Replaced the starter, fuel filter and the rear main cover and seal. I also took apart and cleaned my lower engine block grounds (more on this later).


I installed the rear seal with an align-it tool and took my time and did it by the book.


The screw-up: The whole project stretched out about 5 months and when I put my starter back on I, brain-farted and connected the small black/white block ground on the pass-side above the starter (that I removed to clean) to my starter + terminal. Besides killing my battery and powering my radio full-time I did not notice any other ill affects from doing this.

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UPDATE: The BLK/WHT ground I referenced above is wire 451 and attaches to the G106 ground. It provides grounds for:
1. Powertrain control module
2. IGN mini relay
3. Throttle Actuator control (TAC)
4. MAF sensor
5. EVAP Purge switch

Now I understand why the cylinder fired when I re-connected the battery.
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Until...

Before I figured out I connected the ground to the starter; I briefly turned the car over with the ignition switch a couple times to make sure my starter worked and I had rigged my new neutral safety switch correctly. My battery kept dying (obviously) so after a recharge I was reconnecting the battery to troubleshoot the drain and there was this LOUD BANG from the engine area. Literally sounded like a gunshot!


I looked around and everything seemed fine, but noticed a little smoke coming from the headers (H-Pipe was still off), so I assumed somehow there was gas in a chamber that lit-off when I reco-d the battery (with that ground still connected to positive).


I figured out my error, reconnected everything right, re-charged my NEW optima, put the exhaust back-on and the car started perfectly fine, but almost immediately it dumped all the oil from the rear main seal area. Not leaked, DUMPED!


My question is this: could that loud bang from wherever, have caused enough case pressure to blow out the rear seal?


I get that if I screwed up the alignment I'd get a leak but the way its dumping, the seal can't be in place anymore. Will verify this when I (sigh) take everything out again this weekend.

 

A whole bunch of what-ifs.

Basically just see how the seal looks when you take it out.
You mentioned changing the rear cover, perhaps it's not centered around that crank.

 

There is a WELSH PLUG (basically a freeze plug) in the end of your crank shaft. LS Engine cranks are hollow. It seals the inside of the engine from the outside. If that plug becomes dislodged, you will get a very large oil leak. (when the engine is running)

I do not see how much oil can come out if the engine is not running but some what ever is remaining inside the crank could have leaked out or in your case BLEW OUT.

Sorry for the bad news but give that a look.

Let me know what you think.

Bill

 

Oh the engine was definitely running that's when it started leaking. I was just about to started my auto-trans fluid fill procedure.


Is there any way the input shaft from the Torque tube (TT) could contact and push in that welsh plug? I did replace the guibo's and forward bearing on the TT, but I don't see how that would or could extend the length of the shaft.

 

I don't know but, the crank welsh plug is something to check out!

Did you properly tighten the clamp bolt on the flywheel/input shaft assy?

BC

 

I left it finger tight per the install procedure which tells you to run it in idle for min 10 minutes before you tighten and torque that collar bolt. I though this was weird but that what I did.

 

YEP,,, That's what you were suppose to do!

 

Before you freak out too much, I would get a mirror and a good strong light and check the OPS and Crank Sensor behind the manifold to be sure you do not have a leak there.. Easy enough to do..

Bill

 

I will definitely check that. easy enough to see how that could get damaged when the engine rotates back. Although, looking up through the rubber plug at the flywheel and plate, its drenched and running down from there around the input shaft so I don't think I will get that lucky. Just keep wondering if that loud bang blew out the seal and what else it may have damaged.

 

Pressure building up in the crank case perhaps.
If you have a clogged PCV valve then the crank case may not be able to breathe and enough pressure could build up to blow out the seal, especially if you greased the outer part of the seal putting it in.

If that is the case then I would also be curious if there is excessive pressure due to poor compression and blow by gasses.

I am a little curious as to why the first seal would have failed. Likely the same reason.

 

Did the noise sound like a cork popping out of a bottle of champagne?

 

trans loud bang...... i'm guessing this is an automatic it?

you sure its engine oil? sounds like you didnt seat the torque converter and broke the bump in the trans

 

No sir, more like a gunshot...almost sharted myself...it scared me so bad. The cross pipe was off so maybe that's why it was so loud.


Afterwards there was a little smoke coming out of the headers, so I'm thinking when that ground was connected to power that maybe it caused the plugs fire as I was hooking up the battery. Key was off and out of the ignition btw.

 

Haha, yeah its an auto and definitely engine oil. I wish it was the tranny cooling lines the connect by the bell housing, that would be easy.

 

Could the PCV lines or valve have been damaged when the drive line was removed and the engine tilted back? Do they run behind the manifold?


Also the leak was almost instantaneous and the engine was at idle.


As for the seal...I read much debate online about putting oil on it vs. not. In the end I used oil to align it with align-it tool but wiped it off after wards with just a clean rag. Maybe I should have used solvent or alcohol to get it completely oil free?

 

Is it possible that you installed the seal in the retainer backwards, that would allow oil to pass right by the seal.
Just a thought

 

I checked all that and the back of the block is fine and oil free. The leak is coming from INSIDE the bell housing. I got a mirror in there and while I cannot see the rear seal, I can see the input shaft where it sits in the crank recess and I don't any see evidence of oil in there.

 

The loud bang was most likely a hot wire shorting to ground. I have heard lots of those working at a panel shop, when they spot weld the studs to the panel, it makes a sound like you described.

 

I definitely got that right. I had to use 10x magnifying glass to see the tiny print "THIS SIDE OUT" so I made sure of that.

 

Thought that too at first, but in my case I had a ground connected to a + wire...then I hooked up the battery. I looked everywhere for damage and smoke and all I saw was thin smoke coming from the headers and slight burnt smell there.


After it was connected right the car fired right up and idled smooth with no lights/codes. Then it leaked out...