Coolant leaks past exhaust manifold mounting studs.

[moh_fox]

Hello!
Ever since I purchased my car, I have been experiencing coolant loss. My engine is a 383. In an effort to resolve the problem I began going through the cooling system piece by piece and correcting anything that appeared to be moist or leaking. Once I had all the hose clamps tightened or replaced, thermostat neck gasket changed, upper and lower radiator hoses changed, radiator cap and 26" radiator replaced, I was still leaking coolant. To my surprise, I then discovered that coolant was leaking from my exhaust manifolds! In particular from 4 studs that thread into the water jacket of the heads. The first irregularity I observed was that the exhaust manifolds were installed using gaskets. It was my understanding that B engine Mopars do not use gaskets where the exhaust manifold meets the head. It is supposed to be metal on metal. Anyhow, I removed the exhaust manifolds and gaskets, and could see where the coolant had leaked by the gasket and had moistened the adjacent exhaust port in the head. Also, when I removed each stud, it appeared that they had become somewhat corroded by being continuously soaked.

Does anyone know how to correct this? I have never seen this issue before. I cannot believe coolant was leaking by one stud, say nothing of the fact it was leaking by 4 studs! Under pressure, it must have been leaking like hell. No wonder I was constantly losing coolant. Was this caused because exhaust gaskets were used? Were the studs too loose? Is there some kind of sealant that can be used that will withstand the exhaust manifold heat?

Any ideas would be greatly appreciated.

 

[tallhair]

All the info you need regarding sealing the bolts that go threat the water passage are here:

http://www.forbbodiesonly.com/mopar...-quot-not-so-much-quot/page2&highlight=teflon

Possibly other problems you may have to contend with though and depending on the stud corrosion you should probably pick up some replacement studs

 

[RustyRatRod]

I'm beginning to think maybe we should have a permanent tech area somewhere on here. This and stuff like correct rocker shaft installation comes up a lot. It's easy stuff to make mistakes on too.

 

[KING BEE]

moh_fox

I truly feel your pain. I have a 69 SuperBee Clone. I pulled the motor and did a complete rebuild and the last issue I have had is the 4 exhaust / header studs leaking coolant. As of today, and I just looked under the car and there are no leaks at all, Thank goodness.

I will tell you what I did and I have talked with plenty of Mopar guys and mechanics about this issue.

First - Your photo shows that you have the exhaust manifolds completely off. What I would do is clean every hole out with a tap and blow them out with an air compressor. Make sure the holes are completely dry before moving on.

Second - Use Ultra copper High Temp RTV by Permatex on either every bolt or on the header studs. I personally bought ARP header studs and used the RTV on every header stud. Stick the tube in the four holes that go into the water jacket and squeeze a gob of RTV in the hole.

Third - After you put the header studs or bolts back in with the exhaust manifold, leave it set for two or three days to cure. Once cured, you can refill your radiator.

Last step - Now some will take exception to this, but it worked for me. I went to the local parts store and bought a small blue bottle of "K Seal". It is similar to the old Barrs stop leak. Except this is a liquid. Follow the directions on the bottle. Shake it up, pour it in and run the car up to temp. It says it will seal any leaks in 1 to 3 minutes. Personally, I ran my car for fifteen minutes or more to ensure the opening and closing of the thermostat.

I have been dealing with the leaking header studs for quite some time, (almost a year) and what I have done has worked with no problems and no leaks. It is JMHO, on how to remedy your problem. It worked for me and everything is good to go.

And to your comment on the gaskets. I have Hedman headers on my 440 and I used the crush type header gaskets and have no problems with them.

Good luck with your problem and let us know how it turns out.

 

[moh_fox]

Hello Gentleman!

Thank you for all your assistance in this regard, it is very much appreciated.
King_Bee, I will try your procedure, however I have reservations about running the tap to clean the holes, only because several people have warned against it, saying it sometimes exacerbates the issue. I don't know because I never tried. I will however clean and dry the holes as you say, install new studs with the Permatex, and let everything cure a few days. I will then run the engine, to heat and pressure up the cooling system several times. If I detect any leaks after the foregoing, I will then go the the "K-Seal".

I will keep you posted.

Greg

 

[coloradodave]

You don't want to run a tap through the holes as you're not trying to cut new threads. Use a 'thread chaser' to clean up the threads and a round wire brush with some brake cleaner. I use ARP thread sealer and have had great success sealing some frustrating seeps.

 

[scotts74birds]

I have had great luck with Permatex 597, and 562. These are both hi-temp, and pressure sealants. They're both more than capable to hold the coolant in, and retain torque for threaded connections.