The rear of my intake manifold is leaking oil. It’s a blown application, and the leak is not major. I plan to clean the area with brake cleaner and force as much silicone as I can in there. Are there any tricks to this? I will pull off the intake but I hope to avoid that until the off-season.

I have done this on a few motors over the years. You have to clean the leak area well, as it appears you did. The only silicone I have had any success with for this type of leak is "The Right Stuff". Ultra Blue and Ultra Black don't do well for this type of patch. The Right Stuff is the best there is!!!

Wette vette beat me to it,the "right stuff" is made by permatex,most carquest stores have it,its like epoxy when it drys. When putting a intake on any v-8 chevy its best to throw the manifold end seals away and use that stuff off the get go. Advance auto and autozone should have it too. If you wipe area with laquer thinner and paint it on there liberally you should be able to get the thing to seal. We have washed off leaking small block timing covers where someone changed the chain and couldn't get it to stop leaking and sealed it with that stuff in place,Smitty

That's the type of insight I needed. I would have used ultra black. Thanks guys-

The best stuff I've used to seal oil leaks it Permetex Ultra Copper.
Used it in place of valve cover gaskets on my old truck. Drove it for 100k with no leaks.

But actually you should pull the intake and fix it right. Injecting RTV may work, but I wouldn't trust it.

Iggy,the great stuff is even better than copper rtv. Its like a rubery epoxy once it cures,Smitty

Do you really want to risk an engine to save a couple hours work ?....No Way would I try this

Birdog,
Intake end seal leaks are normally more of a pesky mess than a detriment to the motor. In this case I would definately try to seal it up externally before pulling the intake. There is always a chance for problems when taking things apart that don't need to be taken apart as well.

Craig

I understand ya...Just that chance of a Vacumn leak is enough to scare me tho !

I have used just plan old silicone from the hardware or autoparts. Last year I had oil leaking out the front. Went thru all the trouble to remove intake & replace gaskets. Shortly latter started leaking again. Went & got silicone put in there & stopped the oil leak. Latter the rear started to leak & then did the same. This year when I had the motor apart & instead of using the gaskets that go on the front & back I just put silicone on it. Solved all the problems.