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Old 09-06-2017, 10:40 AM   #1
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infamous rear intake oil leak

Hey Guys,
I have a small rear intake leak on the passenger side of engine. The last time I addressed this issue I used factory GM side gaskets and
heavy bead of ultra copper rtv on the ends. Manifold was torqued properly and it sat for 2 days before putting back to service. Still a small annoying leak! I don't have to be concerned about passing emmissions and was thinking about removing that flexible egr metal tube. The end that is attached to my intake is already blocked off. How can the exhaust end be
blocked off? Do you think this would help?
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Old 09-06-2017, 04:03 PM   #2
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Re: infamous rear intake oil leak

Hey there,the ultra copper silicon you used,i tried that and i wasn't happy with it,i heard the black silicon is good,but.....there's a gray silicon that holds up way better than the copper silicon,as for that egr pipe mines deleted n i have the block plate on it. But it was done because the long tube headers I have.
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Old 09-06-2017, 07:33 PM   #3
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Re: infamous rear intake oil leak

SJM Manufacturing makes blockoff plates for the EGR valve mount on the intake, corrugated tube connection on the intake manifold, and for the connection on the exhaust manifold.

SJM Manufacturing, Inc. (724) 478-5580

I bought mine from SJM, and for the connection on my headers, I cut the end flange off the corrugated tube, and sandwiched the blockoff plate between the thick end flange and the exhaust manifold. That made a better seal, in view of the single bolt on the exhaust manifold connection.

https://www.camaroz28.com/forums/mem...dcp04377-6325/

If you've already blocked the intake manifold end, you've reduced the heat exposure significantly. Most likely the problem arose from the repair procedure. Did you use dowels or studs in the head bolt holes on one side to guide the manifold down on the RTV, to avoid any sliding? Did you use a two-step torquing, following the required sequence?

From Shoebox

http://shbox.com/ci/ci296.jpg

http://shbox.com/ci/intake_sequence.jpg

The shop that built my stroker routinely used the ultra-copper RTV on the many LT1's they built, including mine..... no problem. If you look at Shoebox's photos, appears he used copper. Both mine and Rob's kept a functioning EGR system. The Permatex copper has a max temp higher than any other RTV they make.

http://shbox.com/1/egr1.jpg

http://shbox.com/ci/ci295.jpg
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Old 09-06-2017, 09:00 PM   #4
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Re: infamous rear intake oil leak

I used the Shbox method with the ultra-copper and the studs with great results. If you don't use the studs, one little movement in the wrong way and your install could be all for nothing, and you won't be able to see that you screwed it up. Did you overlap onto the intake gaskets with the ultra-copper ?

I know some people have been successful not using the stud method, but I didn't feel it was worth the chance to ruin it after all that work.

Last edited by gaedbo; 09-06-2017 at 09:02 PM.
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Old 09-07-2017, 08:19 AM   #5
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Re: infamous rear intake oil leak

Thanks, for all the tips fellas. Gonna try again. Might try dimpling the china wall also.
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Old 09-07-2017, 08:37 AM   #6
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Re: infamous rear intake oil leak

Super clean surfaces also help.
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Old 09-07-2017, 09:42 AM   #7
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Re: infamous rear intake oil leak

Also, the most important step is to make sure the sealant cures before even starting the engine. Let it sit for 24 hours. Then recheck the torque on the intake bolts by running through them using the proper torque sequence after a few heat cycles.
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Old 09-07-2017, 10:59 AM   #8
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Re: infamous rear intake oil leak

I have always use Permatex Black "ultra" RTV. It is good for high heat. On gaskets the Felpro "printo" seal type (has blue sealant around each port)
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Old 09-07-2017, 05:59 PM   #9
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Re: infamous rear intake oil leak

Quote:
Originally Posted by Chimera96 View Post
I have always use Permatex Black "ultra" RTV. It is good for high heat. On gaskets the Felpro "printo" seal type (has blue sealant around each port)
yea I heard the black has good high temperature resistance,i seen that in shoebox pics there's studs in the back in the intake manifold,are the studs better for getting a good torque?
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Old 09-07-2017, 06:47 PM   #10
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Re: infamous rear intake oil leak

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Originally Posted by 94Z28LS1toLT1 View Post
yea I heard the black has good high temperature resistance,i seen that in shoebox pics there's studs in the back in the intake manifold,are the studs better for getting a good torque?
There is black and there is black "ultra" RTV...get the ultra

studs???. The reference to using studs is for the alignment placing of the intake onto the motor without "sliding" it which can FU the RTV seal area on china wall.

You just get some threaded stud stock the size of the intake bolts and use 1 on the just one side (likely the closest to you on install) front and rear as "guides to set the intake. You could also use short pieces of wood dowel or drill bits that easily fit in the block holes as a "guide tool"
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Old 09-08-2017, 06:11 AM   #11
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Re: infamous rear intake oil leak

Here is what I did.....A Test Run

Install the intake gaskets on both sides.

Install the studs (Remember, after the intake is in place, and you install a couple of bolts loosely to keep it in place, you need to remove the studs).

With a Dry Run.... NO Sealant Yet.....Install the Intake to see if you clear the studs as you a placing the Intake, and lower it down, and see if you can get the studs back out.

If you have any problems, you can correct how you are doing it without ruining the sealant if it had been applied. If you are good to go, remove the Intake and now apply the sealant and go for it.

You can use extra bolts with the heads cut off, threaded rod, set screws..... I believe the thread is 3/8-16 thread. I wouldn't recommend using wood dowels, because if they break you now have a new problem to deal with.

Last edited by gaedbo; 09-08-2017 at 02:54 PM.
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Old 09-12-2017, 07:39 AM   #12
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Re: infamous rear intake oil leak

Quote:
Originally Posted by shoebox View Post
Super clean surfaces also help.


Hey Shoebox, One of your photos shows ultra copper rtv going up the
sides of the heads approx.one inch. Looks as if this is applied before the side
gaskets. Just a bit confused. Should the side gaskets be installed before the
rtv?
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Old 09-12-2017, 10:16 AM   #13
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Re: infamous rear intake oil leak

Quote:
Originally Posted by frankrizz View Post
. Should the side gaskets be installed before the
rtv?
yes...and use the Felpro "printo" seal intake gaskets
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Old 09-12-2017, 10:51 AM   #14
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Re: infamous rear intake oil leak

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Originally Posted by Chimera96 View Post
yes...and use the Felpro "printo" seal intake gaskets




Thanks for making that clear.
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Old 09-12-2017, 04:23 PM   #15
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Re: infamous rear intake oil leak

I don't think it makes a lot of difference. Never had a leak in that location.
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