Massive oil leak after R&I engine. Ideas?
10-02-2016, 12:44 AM
#1
On The Tree
Thread Starter
Massive oil leak after R&I engine. Ideas?
Longish story, so bear with me... lifters started making more and more noise. That coupled with the fact that there was a small oil leak that had caused years of oil, dirt, and grime buildup, I decided to pull the 5.3 on my Tahoe. The game plan was to reseal the whole engine and do lifters at the same time with it on the stand. Come to find out, one of the lifters ate the cam, so I tossed in another 5.3 cam I had laying around at the shop. Put a set of shaved 241's on to replace the less than desirable Castech 706's and called it good.
So, I get everything back together the other day and start the thing up. Fires right up without CEL's or any weird surprises. Runs great. I get to checking for leaks and there's probably half a quart of oil puking out onto the ground. The oil is spilling at a good rate from between the oil pan and trans. Right away, I thought the rear main seal got snagged on install and it's the culprit of this "Exxon Valdez" like spill.
Yesterday (Friday) I yanked the trans. The rear main seal looked damped, but didn't seem to be the culprit. Hard to tell, because oil was everywhere and everything is clean. I got to thinking and remembered that I had replaced the o-ring on the camshaft position sensor with a o-ring out of a generic kit (bad Idea I know). So I yanked out the sensor and sure enough it was damp. Not dripping mind you, but damp, and was for sure leaking a bit. Thinking I had it licked, I put everything back together and fired the truck up... 2 minutes into running... leaking.
Today, my dad goes over to the shop and pulls the trans. He's convinced it's the rear main seal because it's damp. Replaces it. Re-installs everything and guess what... oil leak.
Anybody else have any educated guesses? It's coming from (best guess) the mid point of the engine in the bell housing. Valley cover to mid-point of engine are dry. The backs of both heads are dry. Oil pressure sender is dry and brand new. Cap for oil cooler above oil filter is dry. Pan gasket is dry except for where it was leaked down onto. All the necessary corners/joints got their necessary dollops of RTV. The rear main seal housing is getting installed properly with our AlignIt tool from SacCity. I've put probably 20 of these LS engines together in all sorts of variations and never had a problem with leaks of this magnitude.
What am I missing guys?
So, I get everything back together the other day and start the thing up. Fires right up without CEL's or any weird surprises. Runs great. I get to checking for leaks and there's probably half a quart of oil puking out onto the ground. The oil is spilling at a good rate from between the oil pan and trans. Right away, I thought the rear main seal got snagged on install and it's the culprit of this "Exxon Valdez" like spill.
Yesterday (Friday) I yanked the trans. The rear main seal looked damped, but didn't seem to be the culprit. Hard to tell, because oil was everywhere and everything is clean. I got to thinking and remembered that I had replaced the o-ring on the camshaft position sensor with a o-ring out of a generic kit (bad Idea I know). So I yanked out the sensor and sure enough it was damp. Not dripping mind you, but damp, and was for sure leaking a bit. Thinking I had it licked, I put everything back together and fired the truck up... 2 minutes into running... leaking.
Today, my dad goes over to the shop and pulls the trans. He's convinced it's the rear main seal because it's damp. Replaces it. Re-installs everything and guess what... oil leak.
Anybody else have any educated guesses? It's coming from (best guess) the mid point of the engine in the bell housing. Valley cover to mid-point of engine are dry. The backs of both heads are dry. Oil pressure sender is dry and brand new. Cap for oil cooler above oil filter is dry. Pan gasket is dry except for where it was leaked down onto. All the necessary corners/joints got their necessary dollops of RTV. The rear main seal housing is getting installed properly with our AlignIt tool from SacCity. I've put probably 20 of these LS engines together in all sorts of variations and never had a problem with leaks of this magnitude.
What am I missing guys?
Last edited by slvrram; 10-02-2016 at 01:44 AM.
10-02-2016, 01:07 AM
#2
When you changed the rear main seal did you pull the rear housing to install it, or try to install it with the cover in place? There are a couple of oil galleys that the rear cover seals against and if the oil pan and housing arent properly aligned it will cause issues, i have had better luck hand tightening the rear and timing cover bolts, tonwhere they are flush but can still move slightly, then installing the oil pan torquing it down and then torquing the front and rear covers.... If the pan is misaligned it will throw everything off, is the truck 2 or 4wd? Try loosening the oil pan, pulling the rear main housing and then torquing it all back down with a new seal... If you didnt already try replacing the oil galley dumbell plug thing behind the rear cover...
10-02-2016, 01:41 AM
#3
On The Tree
Thread Starter
You more or less explained how I put the covers on.
1)A little less than hand tight
2)use the AlignIt tools to line the covers up
3) little tighter on the covers
4)use the tools to press the seals in
5)torque everything to spec.
This method has netted leak free results in the past. It's possible I accidentally bumped the pan when tightening everything. I guess anything is possible at this point.
The truck is 2wd.
What has really interested me in what you've said is about the oil gallery plug... If it's shot, would it leak by the cover? I did reuse this one (usually I replace them). Oil pressure looked good before the tear down.
1)A little less than hand tight
2)use the AlignIt tools to line the covers up
3) little tighter on the covers
4)use the tools to press the seals in
5)torque everything to spec.
This method has netted leak free results in the past. It's possible I accidentally bumped the pan when tightening everything. I guess anything is possible at this point.
The truck is 2wd.
What has really interested me in what you've said is about the oil gallery plug... If it's shot, would it leak by the cover? I did reuse this one (usually I replace them). Oil pressure looked good before the tear down.
10-02-2016, 01:55 AM
#4
I usually install the seals prior to installing the covers, with the seal install tool(white ring) installed going on. As far as the plug... There is an o ring on them, and they are in the galley straight after the oil pump, so its entirely possible if the oring is shot it could leak past the seal!!
10-02-2016, 03:48 AM
#5
On The Tree
Thread Starter
I guess that's the next thing I will start with. I should have replaced it while it was out. Wouldn't the oil pressure just bleed back down into the pan though? I feel, and by looking at the parts pieces, that downwards into the pan would be the path of least resistance.. Not through the rear seal or cover gasket.
10-02-2016, 06:25 PM
#7
On The Tree
Thread Starter
Dad pulled it again today. More or less waiting on parts now. Went ahead and ordered a handful of diverters, another seal, and another cover gasket, along with a new cover. Ordering a cover is a waste, because I have no less than 6 sitting on the shelf, but just want this to be the last time this thing comes out for a while.
I'm working nights until Tuesday, so it'll be at least until then before I can put my hands on it and get some pics.
He did note today that it looks like a couple of the cover bolts look like they were leaking through. I wonder if the cover gasket may be compromised somehow. Food for thought I guess.
When I have a couple free minutes, I'll post up some pictures. I also intend to run it with the trans pulled for a short bit to actually see this leak with my own eyes.
I'm working nights until Tuesday, so it'll be at least until then before I can put my hands on it and get some pics.
He did note today that it looks like a couple of the cover bolts look like they were leaking through. I wonder if the cover gasket may be compromised somehow. Food for thought I guess.
When I have a couple free minutes, I'll post up some pictures. I also intend to run it with the trans pulled for a short bit to actually see this leak with my own eyes.
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10-06-2016, 10:09 AM
#10
On The Tree
Thread Starter
So I attached some pictures of what I'm working with. The cover looks great. Not perfect, but I've put a lot worse back together without issue. The diverter looks okay except for the couple scratches from me screwing with it. All the gaskets looks intact and rear seal looked good as well. I'm at a loss.
I've put new everything on this morning and hung the exhaust on it with the neutral safety switch as well. Plan to run it and see if I can get it to leak again. On the very first intall, it took about 20 minutes of run time for it to start. Once it started and whatever was compromised, it would leak right away every time the truck was started.
I've put new everything on this morning and hung the exhaust on it with the neutral safety switch as well. Plan to run it and see if I can get it to leak again. On the very first intall, it took about 20 minutes of run time for it to start. Once it started and whatever was compromised, it would leak right away every time the truck was started.