Leak from the back of LS9 head gasket??
06-07-2016, 11:19 AM
#1
Leak from the back of LS9 head gasket?? Since the rebuild of my engine I have pretty bad oil leak all over top/rear of my engine. I tried to trace the leaks and it seems like the most is coming form the driver side head gasket, about 2" from the "top". It's where the paper with the sticker goes in the picture. Is this even possible???
I have LS6 intake if that matters and during rebuild I put LS9 gaskets.
What's strange too, looks like oil is pouring to both sides of the engine, I have oil dripping from the starter too... Also I have small leak from the oil pan gasket but it's really tiny.
Any ideas what's happening??
I have LS6 intake if that matters and during rebuild I put LS9 gaskets.
What's strange too, looks like oil is pouring to both sides of the engine, I have oil dripping from the starter too... Also I have small leak from the oil pan gasket but it's really tiny.
Any ideas what's happening??
Last edited by Vetal; 07-07-2016 at 07:24 PM.
06-07-2016, 08:05 PM
#3
Since the rebuild of my engine I have pretty bad oil leak all over top/rear of my engine. I tried to trace the leaks and it seems like the most is coming form the driver side head gasket, about 2" from the "top". It's where the paper with the sticker goes in the picture. Is this even possible??? I have LS6 intake if that matters and during rebuild I put LS7 gaskets. What's strange too, looks like oil is pouring to both sides of the engine, I have oil dripping from the starter too... Also I have small leak from the oil pan gasket but it's really tiny. Any ideas what's happening??
It might be dripping and once it drips it'll show up everywhere even under the tranny bellhousing area
06-09-2016, 10:57 AM
#9
The LS7 gasket is made specifically for the LS7 block.
The water passages on top of the cylinder are shaped just a little different vs the ls1 block.
Idk if this is why you are leaking oil, can you verify its the head gasket and not the valley cover?
You have a gasket under the valley cover right? Sorry had to ask lol
As far as the oil pan leak, did you follow the alignment procedure and use rtv on the 4 corners where the front and rear cover touch the pan?
The water passages on top of the cylinder are shaped just a little different vs the ls1 block.
Idk if this is why you are leaking oil, can you verify its the head gasket and not the valley cover?
You have a gasket under the valley cover right? Sorry had to ask lol
As far as the oil pan leak, did you follow the alignment procedure and use rtv on the 4 corners where the front and rear cover touch the pan?
06-10-2016, 10:35 AM
#11
The LS7 gasket is made specifically for the LS7 block.
The water passages on top of the cylinder are shaped just a little different vs the ls1 block.
Idk if this is why you are leaking oil, can you verify its the head gasket and not the valley cover?
You have a gasket under the valley cover right? Sorry had to ask lol
The water passages on top of the cylinder are shaped just a little different vs the ls1 block.
Idk if this is why you are leaking oil, can you verify its the head gasket and not the valley cover?
You have a gasket under the valley cover right? Sorry had to ask lol
You can see from the pic that leak is originating ~1.5" from top of the head, so doesn't look like it's coming from valley cover... I have suspicion that valley cover is leaking oil on passenger side, but on drivers side it absolutely looks like oil is coming from head/HG/block mating...
It's coming from the middle of the left side mating surface, not on the corners...
07-07-2016, 07:30 PM
#15
It's 3am here and I might be asking stupid question, but... Can oil get into the intake runners from the head ports? 
I've removed intake, cleaned everything, put intake back and ran the engine for few minutes. Then I pulled the intake off and all ports in the heads were covered with oil and most of intake runners too, however it seems that oil is coming FROM head ports into the intake, and not vice versa like I was expecting (if PCV was sucking oil into the intake).
Is this even possible???
I've removed intake, cleaned everything, put intake back and ran the engine for few minutes. Then I pulled the intake off and all ports in the heads were covered with oil and most of intake runners too, however it seems that oil is coming FROM head ports into the intake, and not vice versa like I was expecting (if PCV was sucking oil into the intake).
Is this even possible???
07-07-2016, 08:51 PM
#16
It's 3am here and I might be asking stupid question, but... Can oil get into the intake runners from the head ports?
I've removed intake, cleaned everything, put intake back and ran the engine for few minutes. Then I pulled the intake off and all ports in the heads were covered with oil and most of intake runners too, however it seems that oil is coming FROM head ports into the intake, and not vice versa like I was expecting (if PCV was sucking oil into the intake).
Is this even possible???
I've removed intake, cleaned everything, put intake back and ran the engine for few minutes. Then I pulled the intake off and all ports in the heads were covered with oil and most of intake runners too, however it seems that oil is coming FROM head ports into the intake, and not vice versa like I was expecting (if PCV was sucking oil into the intake).
Is this even possible???
On aftermarket heads you must rtv seal the intake rocker bolt holes and some intake manifold bolt holes. They break thru when cncing. Also I think it happens when u get the gm heads cnc'd as well.
