Coolant Leak from Manifold?

[Mocktwo]

I have a 440 Magnum in my 72 Challenger. Stored for the winter I noticed coolant in the floor tray I had under it. Tracing it up, I see coolant on the manifold to exhaust connection (driver's side). The side of the engine is dry, soft plugs are dray. I am perplexed ... ideas welcome before I start to take things apart ...

 

[greatscot3]

In the iron 440 heads the exhaust manifold bolts actually screw into the water jackets (poor design).
If you install the exhaust manifolds without putting sealant on the ends of the studs they will almost always start to leak coolant.
Edelbrock aluminum heads have the exhaust manifold deck extended .125" and they closed off the helicoil threaded stud holes to the water jackets.

 

[Mocktwo]

Ugh (thanks), All manifold bolts or just some?
A sealant like Permatex?
Pull one bolt at a time and seal, or remove the manifold?

 

[DetMatt1]

Ugh (thanks), All manifold bolts or just some?
A sealant like Permatex?
Pull one bolt at a time and seal, or remove the manifold?

You will have to drain the coolant from the block before doing this and you can do it one screw or stud at a time.

 

[tonysrt]

B, RB and hemi's don't have water through the intake manifold. Probably an exhaust manifold bolt that is leaking, unless the head to the block is the culprit.

 

[moparlee]

Ugh (thanks), All manifold bolts or just some?
A sealant like Permatex?
Pull one bolt at a time and seal, or remove the manifold?

Studs are preferred over bolts, that's what came from the factory.
Any good thread sealant, don't use RTV.

 

[Chryco Psycho]

I would use teflon tape & Liquid teflon

 

[greatscot3]

Yes, drain at least some of the coolant because when you pull even one of the manifold bolts or studs it will start pissing coolant all over.
I used Permatex grey on my '68 iron heads before I put the new Edelbrock heads on it and it held up well enough.
One thing that some people hate to hear is using Bars Leak if you can't get something to seal.
One thing that is not common knowledge is that for many years, GM used Bars Leak in brand new cars that had never leaked anything before they sent them out the door.
They did this because it was easier doing that than getting a new car back from a customer to fix a leak after the fact That's really true. I didn't believe it at first and I looked into it and found out I was told correctly.
If you are interested, this is a thread from BBodiesonly about the same manifold bolt/stud subject.

440 exhaust manifold head stud keeps leaking

I’ve put Teflon pipe thread sealer (paste type) on this stud twice and it works for two weeks and leaks again. What should I use to stop the leak?...

www.forbbodiesonly.com

 

[Mocktwo]

greatscot3, I have the Permatex and I will keep Bars leak in mind. Thank you.

 

[Rons340]

I have experienced the same issue with 340 engines. The outer studs on the front and rear of the heads penetrate the water jacket and will certainly leak without sealer applied. I use liquid teflon on everything coolant related. No further issues!
Watch those bolts in the timing cover/water pump area also!

 

[Mocktwo]

I have experienced the same issue with 340 engines. The outer studs on the front and rear of the heads penetrate the water jacket and will certainly leak without sealer applied. I use liquid teflon on everything coolant related. No further issues!
Watch those bolts in the timing cover/water pump area also!

Thanks. Do you have a brand you like? High Temp?
What I found was "Permatex 59214 High Temperature Thread Sealant"

 

[Rons340]

This is what I have used for many years. $8.99 at the Zone.