To use sealant or not to use on 258 intake manifold

[OEM1984CJ7]

I pulled my motor to clean it up and replace the valve cover/gasket that has been leaking for 10yrs or more, water pump and oil pan gasket and just to clean up the engine compartment. I went ahead and got the Fel-pro exhaust/manifold gasket and my neighbor who has a CJ5 came down to see what was going on. He noticed I was not going to use any sealant on the exhaust gasket or the intake manifold and just install them bare with anti-sieze on the bolts and said I should have used the gold heat sealant on both of them. I have never used any sealant on either gasket and never had problems. Should I be using sealant on the intake manifold?

I also got the one piece Fel-pro oil pan gasket and mfg. states to use a slight amount of the black rtv on the four corners on front/rear on the U and thats it. It has the copper bolt reinforcements in it also. Pretty slick looking gasket.

I would think not but I told him I would find out for sure.

thanks!

 

[CJ007]

I have a mechanic friend that suggested that a while back and I do. I don't see how it can hurt. When you wheel alot they come loose either way. He said let it set up a little so it acts like a rubber gasket vs squeezing out.

 

[Old Dog]

I've seen people do it both ways, didn't seen to make a differance.

 

[CJim7]

I've seen people do it both ways, didn't seen to make a differance.

Same here.

If you are going to use a sealant on the exhaust/intake manifold I would highly suggest using copper spray gasket. RTV has a way of finding it's way into critical engine parts....the spray gasket bonds quickly and builds a thinner more even coat on the surface.

 

[IOPort51]

I don't use sealer on anything that doesn't hold water or oil and even then I don't like to.
just an opinion, I don't really think it would hurt as long as you don't get carried away with it.

 

[OEM1984CJ7]

I pulled the old man/intake off and no gasket on the exhaust and the intake gasket had no sealer. I will go back with the exh gasket and overlay the intake gasket and bolt her back up. A good cleaning first of course. I am missing the rear exhaust stud/nut , I assume that is where my small exh leak was coming from.

thanks.

 

[IOPort51]

I will suggest you put a strait edge on the surface to check both manifolds. I have had problems with erosion/warping at the ends of the exhaust manifold to the point that it was a replacement rather than a re surface.

 

[AOrangeWIP]

Is it true that you are suppose to use sealant or a gasket, but never use both at the same time? I've always heard that, but I like to put some sealant on gaskets just to be on the safe side.

 

[littleriverrat1]

To seal or not to seal that is the question! While most gaskets are made to be used without additional sealants or sprays there are a couple different reasons why mechs use it anyway. One being the light application of a good sealant or RTV helps hold hold the gasket in place for assy. The second is for the obvious, troublesome areas like back corners, horseshoes and joggles. In any event be thoughtful not to use to much. Pesonally I prefer to use the lightest possible amount to insure I dont loose place during bolt up.

 

[1986cj7]

Now on a ex/intake gaskets are mosty a metal type not sure I've worked on tractors most my life. My father and I have used a little greese to hold gaskets in place. Has anyone heard of this or is this just something the old timers that didn't have sealant on hand did. This may not inply to ex/intake gaskests. Just asking. Maybe greese may eat some gaskets up not sure.

 

[MN CJ7]

The AMC 258 i6 / 4.2l is a long engine and is know for leaking.... oil pan, valve cover, intake, exhaust, all of them..... These are all long and all known to leak...

A few thougths.

The RTV or sealeant.... the labels say not for gasoline service.....
Label says that if it touches gas not good application.
So the carb mounts and intake manifolds are not good applications for RTV.

The exhuast manifold has a heat issue with most RTVs and the copper may hold up... but is it needed?

I am in the camp that RTV is not needed on the intake and exhaust gaskets. Do not use RTV where there is gas service and it states that on the label of the RTV.

There are TWO gaskets for the the AMC 258 i6 / 4.2l ... one for the cast iron manifolds and one for the alumium intake...
Aluminum and steel touching is a corrosive situation... galvonic corrosion... add heat/higher temps and happens even faster... The more modern alumimunm intakes use different gasket material to stop this chemical reaction and keeps the block cast iron from touching the alumium intake....... So owners need to ck the intake material to select the correct gasket set... Alumium and get a gasket set from the 83 time frame... Cast iron and get a gasket set from the late 70s. I have a 78 CJ with a alumium intake so I need a gasket from the 80s.

High Tac is a gasket hold material.... This is very usefull for the long gaskets on the oil pan and valve cover. I use some of it to hold in spots along the gasket path to hold in place. I also use RTV on oil pan and valve cover with a premium fel pro gasket. Let is set up over night before the torque up to spec. If you plan on going in there a few times maybe RTV is not the way to go.... if you have sound engine and it will be left alone... seal it up. I have yet to have one leak this way... current one is installed for 4-5 yrs. High TAc and permatex product is great when you need 2-3 extra hands to hold the gasket while the cover is added.

There is a order to tighten the oil pan, valve cover, manifolds... Start in center and in a CIRCLE path work your way out. Then repeat several times till torque spec is reached. That make everthing flat and does not over tighten. Look up and record the torque specs for your oil pan, valve cover and manifolds...... this will help lots... so does the circle pattern

Look at you tin / metal covers is the bolt holes are dished or bent.... they need to be straightened.
I used the end of the wooden work bench and fixed the oil pan and valve cover holes before I painted them. This helps with a proper prep and surface so they seal up better. If already painted use some making tape on the ball peen hammer and it will save some of the paint from being wrecked.... This step gets missed lots... and can make a big difference.

Use antiseize everwhere.... esp on the manifold bolts that get very hot and rust up that much faster...