Leaky intake manifold gasket project

[rogold]

     A month or so ago, I found a little coolant puddle on my garage floor. Decided to look into it now that the cold weather season has set in. After pressurizing the cooling system with a radiator pump tester, I saw a slow drip off the bottom of the engine. Followed the trail of coolant to the top of the engine. It was a slowly oozing up between the intake and the head right below the EGR valve .

     So I pulled the intake yesterday and this is what the gaskets look like. Kinda worse than I was expecting. Surprised it was that kinked and distorted around the ports. Now I am waiting for all the misc gaskets and hoses to put it all back together.

Edited December 15, 2021 by rogold

[2seater]

Check around the water ports, particularly the corner that was leaking. The intake manifold surface will likely be pitted or eroded around that port from galvanic corrosion. If it is and it looks fairly deep, I have had good results filling the erosion with epoxy such as JB Weld and then a flat file to smooth the surface. 

[rogold]

Thanks for the tip! I will check before reassembly.

[Philbo]

On 12/14/2021 at 11:26 PM, 2seater said:

Check around the water ports, particularly the corner that was leaking. The intake manifold surface will likely be pitted or eroded around that port from galvanic corrosion. If it is and it looks fairly deep, I have had good results filling the erosion with epoxy such as JB Weld and then a flat file to smooth the surface. 

Hadn't ever thought of that. Seems like a good idea.  I have done 4 Intake manifold gaskets on older GM cars, including my reatta. All 4 of them were pitted there. All 4 of them I used Permatex Right Stuff only around those ports on the heads.  So far none of them leak.

 

Also FelPro gaskets are the way to go in my humble opinion.

[Ronnie]

48 minutes ago, Philbo said:

Also FelPro gaskets are the way to go in my humble opinion.

I like FelPro to.

[2seater]

Generally I like Fel Pro as well except their head gasket, which has too large of bore, costing compression ratio. For head gaskets, Victor Reinz makes the OE style with the correct bore size and shape. They also have a different style intake manifold gasket which works well in my experience. It doesn’t have the silicone sealing beads which can fall right back into the eroded areas. It is just an alternate choice if needed.

[rogold]

I did go with FelPro intake gaskets, just because of the good luck I have had in the past with them. My car has relatively low miles (93k) so there was minimal corrosion on the manifold. But I would have tried the Victor Reinz if I knew of the different design. The original gaskets had silicone seals around the ports too, hopefully the FelPros last longer.

I am still in the reassembly process. Been spending a lot of time chasing down o-rings and gaskets. 

[2seater]

I should have said, the alternative ALSO works well, not to suggest Fel Pro is substandard, because I use them too. As a matter of fact, if they are not damaged like in the original photos, they can be reused if the silicone beads are in good shape.

 

[Philbo]

15 hours ago, 2seater said:

Generally I like Fel Pro as well except their head gasket, which has too large of bore, costing compression ratio. For head gaskets, Victor Reinz makes the OE style with the correct bore size and shape. They also have a different style intake manifold gasket which works well in my experience. It doesn’t have the silicone sealing beads which can fall right back into the eroded areas. It is just an alternate choice if needed.

 

That's good to know

[Philbo]

Just my opinion alert.

 

I personally swear by this stuff: https://www.amazon.com/Permatex-99070-Right-Stuff-Gasket/dp/B000HBM6PE

 

If you need something to not leak, this is the stuff to use. I have heard that it is kind of a pain to clean off if you need to take it apart, so I typically only use on things that I plan to not have to take apart for a long time (or hopefully ever)

 

For the intake manifold gaskets, i know felpro says to put the gasket on dry, but due to the corrosion issues I have seen, I will smear a thin layer of this stuff around the coolant ports on both the heads and the intake manifold. The intake ports I leave dry. I also put a small bead of it in the corner where the block, head, and manifold come togerher. Mostly because the GM engines in my experience tend to develop an oil leak there. This has been my method and has worked well for me. Ive done it on two 3.8L V6 (incl my reatta), a 3.1L V6, and a 5.7L V8, which all have a pretty similar design. All of them had a good bit of corrosion at those ports. Prev owners had left old antifreeze in them for a long time unfortunately. 

 

I think if there was no corrosion I would consider putting the gaskets on completely dry, but maybe would put sealant anyway to help prevent corrosion. I don't know. However @2seater your method of filling the pitting with epoxy is very interesting to me.  I might have to try that on the next one. Out of curiosity, where did you get the idea to do that?

[2seater]

I agree, the Right Stuff is good stuff😉 The filling the badly eroded areas just seemed obvious to me. Perfect application since it only needs to provide a smooth surface, no real pressure and it is essentially captive.