The fabled exhaust leak from manifold to downpipe

[pjoll84]

HI everyone,

So I’ve been chipping away at this 318… making sure everything is ready to rock for a summer of camping (Sorry its a B200 camper, nothing sexy like your muscle cars lol)

As I was refilling the coolant and waiting for the tstat to open (a few air bubbles decided to coat half the engine bay)… which gave me an excellent clue as to a pretty massive leak between the manifold and downpipe flange. Now I’ve tried to research as much before asking so apologies… but I wanted to hear what you’ve had success on mating these two connections and having no leaks.

I’ve read copper rtv sandwiched between the two…
I’ve read adding a donut to sandwich between the two…
Others say they connect them metal on metal and its fine…

Not a lot of room from above with the doghouse off… so I might have to tackle this from down below and some extensions.

Look forward to hearing what has worked for you. Cheers!

 

[493 Mike]

What does your local auto parts store say? Unless it has a ball and socket style connection it should have some type of gasket.
Mike

 

[AR67GTX]

If you have a large gap red RTV is probably not the solution for that. More like a gasket would be necessary. What does the connection look like? Two flat surface flanges that mate up? A ball and socket connection? Some Chevys use a donut gasket with a sleeve but I’m not sure if Chrysler ever did.

 

[Don Frelier]

Pictures?

 

[HawkRod]

HI everyone,

So I’ve been chipping away at this 318… making sure everything is ready to rock for a summer of camping (Sorry its a B200 camper, nothing sexy like your muscle cars lol)

As I was refilling the coolant and waiting for the tstat to open (a few air bubbles decided to coat half the engine bay)… which gave me an excellent clue as to a pretty massive leak between the manifold and downpipe flange. Now I’ve tried to research as much before asking so apologies… but I wanted to hear what you’ve had success on mating these two connections and having no leaks.

I’ve read copper rtv sandwiched between the two…
I’ve read adding a donut to sandwich between the two…
Others say they connect them metal on metal and its fine…

Not a lot of room from above with the doghouse off… so I might have to tackle this from down below and some extensions.

Look forward to hearing what has worked for you. Cheers!

The stock type manifold connections usually work pretty well with minimal issues.

The gasket type I am familiar with is a donut shaped gasket that is fairly thick and has tapered ends.

These work very well. Although it might be a pain to do, loosen the nuts holding the exhaust flange to the manifold. Check the condition of the donut gasket and replace if needed. If replacement is not needed, just carefully align the donut with the two flanges as you tighten the exhaust - make sure it everything is lined up.

Good luck!

 

[Don Frelier]

Magnum small block manifolds have a ball shaped end.
The headpipe opening is tapered and there is no gasket used.