Drautotech

So I found where the oil is leaking and I was just were I thouht. It is leaking where the intake manifold meets the block in the back under the distributor. It is leaking on the passenger side in the corner.

The werid this is that I put In a new gasket there and covered it with a bonding sealant to make it a tight seal. But once I got it together and ran it again I notice again I'm still dripping oil on the ground and on my catalytic converter making a burning oil smell and smoke. I just put on new cylinder heads would that make it leak?

Is there any way I can seal the spot properly? It was leaking on the other side before I put the gasket in. Now it's the passenger side. I could really use some help and ideas
Thanks Dave c

Joe C

sorry to tell you this, but "properly," is going to require pulling the intake again. I might suggest quality felpro gaskets, and RTV, oil resistant, silicone. make sure all surfaces are squeaky clean, especially the corners where the heads meet the china walls. run a bead of the RTV on the china walls, and at least 1/2" up and on both sides of the manifold gaskets, paying close attention to the corners. the 1/2" thing might even be covered in the FSM. good luck - keep us posted -

wydopnthrtl

Have you checked that the intake to head bolts are still tight?

John A. Marker

with Joe C. Did you use a gasket on the front and rear China walls? Sounds like you did. Recommended fix is to use the intake gaskets and then use Silicone or the Right Stuff on the China walls. Recommended that a 3/8" bead be used and then the intake set straight down...don't slide it in position.

If you want to try this...but no surefire fix. Get a can of brake cleaner with the long spray nozzle and clean the area that is leaking several times. Then hit it with come compressed air to be sure it is clean and dry. Then take 100% silicone or the Right Stuff and put some on your finger or stick and see if you can smear it over the area that is leaking. Let it dry for a day. This might stop the leak so you don't have to tear off the intake again.

Drautotech

I bought a new set of gaskets for everything and they are felpro gaskets. I also have rmv and some silicone I got from work. When I took off the manifold I noticed that the gasket in the corner where it is leaking was slide back alittle and was not sticking into the manifold but the front was fine. I might have slide it back when putting it on. I'm cleaning the tops of the walls clean and hopefully it will solve my problem with these new gaskets for the wall. Thanks for the help guys

John A. Marker

If you have paid attention and done some searches.....they use a 3/8" bead of either silicone or the Right Stuff instead of gaskets on the china wall. The gaskets just did not do the job in the past, which is why the use of the silicone. I have had to replace multiple gaskets on the china wall over the years that failed. Using the silicone I have never had a failure.

chevy john

Which gasket set should I buy. Felpro ? which number?

lotsofspareparts

I bought the Mahle MS15401W gasket set from Rock Auto. What was really nice about it is that it actually comes with formed silicone seals for the china walls.

I applied the Right Stuff just like you normally would and then laid the seals down, little more of the Right stuff, even up the heads/Manifold gaskets in the corners, I am happy to say I am leak free.

The entire top end gasket set was cheap too, like $21 plus shipping.

Jared

ctmccloskey

One important note here guys!!

You really DO NOT WANT TO use "The Right Stuff" on intake manifolds or on China walls as it is VERY hard to remove.

If you used it on the entire intake manifold you might not ever get it off the engine. It is just too good of a sealant in this application.

I agree with John A. Marker about using a good name brand RTV (Specially designed so it does not hurt your sensors) on the china wall in place of the rubber strip gaskets. The real trick with intake manifolds is just getting the surface perfectly clean and rid of any contaminants. I use alcohol prep pads as the final cleaning prior to the application of RTV. Cleanliness is the most important part of this entire project, you really don't want any of the old gaskets of RTV getting into your oil system and the RTV won't stick unless the surface is really clean.

Like others here I too have done this on many engines in my days and the RTV has never let me down yet. You only need to be careful not to use excess RTV.

We have heard horror stories about "The Right Stuff" used on valve covers and such which then become very difficult to remove. To me "The Right Stuff" is a permanent sealant which is not what you want on many car joints. It is however a great product and I have it on my shelf ready to use.

Best regards,
Chris

lotsofspareparts

I just wanted to note that I had very good results using the silicone gaskets for the china walls. They really alleviated some of the stress of having to use a half a tube of RTV on each side of the engine and then come to find out you squeezed it all out when you were wiggling the manifold into it's correct position.

I'm curious to know what don't you like about the china wall gaskets?

The guy who installed the intake manifold back on my engine after it was rebuilt (previous owner) used red RTV everywhere, manifold gasket, header gaskets, front and rear of the intake manifold. Even though this engine had lass than 10k on it, it was leaking oil from everywhere.

I replaced every gasket with the exception of the oil pan gasket when I installed my cam..... and no more leaks.

Jared

chevy john

thanks

ctmccloskey

The China wall gaskets do not stay in place very well during the installation of the intake manifold and need to be sealed with RTV anyway. Many years ago I swapped an intake manifold and used the China wall gaskets. Unfortunately they rolled a bit during installation and failed to seal even with RTV on it. Today I just don't use them at all, it is a better seal when a good bead of RTV is l used in place of the China wall gaskets. In my humble opinion, of course

Too much RTV can be problematic, but not enough is also bad. But again I stress that the surface preparation is 99% of the job and can make or break the fix. If you do use the china wall rubber seals you need to secure them (glue) in place first and let them dry, then add RTV to the top to get it to seal reliably.

I don't think I am the only person here on the CF who does not care for or use the China wall gaskets. Ask around if you don't believe me...

A "Bubba" and his tube of RTV can be dangerous, there is no question about that. Too many folks think you can use it everywhere but on the headers? If Bubba had used "The Right Stuff" to glue those parts together they might not leak but they would not come apart without a fight.

I try to do things the way the factory wanted us to but there are times when I will deviate, like with the China wall gaskets.

When I helped rebuild my 427 we sealed it up properly and it still does not leak after 20 plus years of service. I don't have any drops on my floor under my Corvettes. Obviously I must "know" something about sealing a motor as well. We even sealed the inside of the block before using it using Glyptal on the inside of the block to help the oil return to the oil pan quickly. I built this engine with the help of a master engine builder and he never used the rubber China Wall gaskets either on any of the hundred of engines he built.

The point about using "Sensor Safe" RTV is important as people use the wrong stuff all the time and find out the hard way.

Best regards,
Chris

lotsofspareparts

It's fair enough to not like them because you have suffered issues during installation in the past. I was merely stating that I had good luck with them.

Something else I might add, the china wall gaskets that were included in the Mahle kit that I used had molded in tabs that held them in place during manifold installation. It really was a hassle free installation.

Jared

ctmccloskey

Maybe one of the "brighter" engineers finally realized that we were not using the part as it did not work well as it was designed before. Having positioning tabs would be a great help in holding them in place. I just got used to having to glue them down to get ready to install the intake.

My "Bad" experience was with my 1968 C3 427 BB and that engine block has a seriously thin china wall on the back side. Having to remove the whole intake and do it over cost me another weekend. At least on the 1968 C3's there is room to work on it without having parts all over the place. The C4 is a bit tighter in the intake area.

Thanks for your thoughts! I have not tried a MAHLE set of gaskets as I have been a FelPro addict since I was younger. Those China wall pieces DO look more substantial than the ones I had years ago.

What really cought my attention was "The Right Stuff" you mentioned. I have heard some horror stories about that material being used in places where you need to remove the part later. I must admit that I have seen a lot of leaky china walls that had only RTV on them, frequently it is caused by improper cleaning of the parts. If "A little" RTV works some people must think that "A Lot" is going to work better at sealing. You have to love the Bubba's of the world, may they all buy Asian cars.....and stay away from our beloved Corvettes.

Have a great Labor day weekend Jared!

Best regards,
Chris

I have a daughter who goes to school in Daytona Beach, Florida. She is now in South Carolina hoping to ride out Hurricane Dorian a bit further inland. It is getting exciting here on the South-Eastern seaboard!! The Pacific Northwest sounds real nice right about now.....

lotsofspareparts

In regards to the weather, I have been following Dorians path as well, I have some extended family in Florida and an Uncle or 2 in South Carolina. My family is from the east coast, I was born just outside of Boston. It has been pretty nice around the PNW the past few weeks.

I used "The Right Stuff" on the china walls and where the intake gaskets meet the china walls. I also used it on the timing cover but if worse came to worse.... timing covers are cheap to replace. I can't foresee a problem removing the intake in the future should it become necessary.... a little pry bar goes a long ways when used properly. Some MEK and a heat gun would work great to soften the sealant and then scrape it off. I'm counting on not having to remove it again though, fingers crossed and so far so good.

The Mahle gasket kits are manufactured by Victor Rienz BTW. They felt/appeared to be very good quality. It was my first time using them. I typically try to buy OEM.... but you can't buy an OEM "kit".

Have yourself a fine Labor Day weekend as well Sir, mine has so far been spent installing a new main electrical panel for some future remodeling. Fun Stuff.

Jared

puterami

The last time I did an intake on a 350 (not a Corvette and was many years ago) I found a set of gaskets that had rubber chinawall gaskets with locating tabs. Wish I remember the brand and part number. Worked great with no leaks. Yet, I don't know how they stood the test of time.