Leaking head stud

  I'm always open to trying new products from proven sources, back when we had our parts store, sales reps would give us sample product to try. We would give these to select customers to use in the field & report back.  Some with success, some not.... 

  One that really stood out in my opinion is Hylomar, a polymer gasket dressing that will withstand fuels & oils. The perfect solution to that carb base gasket that will not seal dry.

 https://hylomar.com/en/universal-blue/

 They make a whole range of sealing products...

 Anyway, yes, I will report back on success & or failure of this Permatex product.

When I start the engine and it warms up, it still bubbles up around the top of the stud, between the nut and thread - until the thermostat opens. Then it stops leaking.

Now what?  Leak fix?

I have done this repair twice with the same result. 

     Jim

   Jim

   Jim

I disagree, as sometimes it is the only solution, and there are good products out there that work.

I have used various forms of it over the years without plugging up the radiator with one exception and that was when I got a hole in a radiator out in the boonies and did not have any other choice than to use a can of black pepper from the cook box. That did get me home, but it did run a little hot until I had the radiator fixed. 

I had a crack in the block on an old Ford tractor. The machine shop I use sold me a product they called "cold weld". It was a green ball of something that I put into the water jacket through the thermostat port. It sealed the crack with no problems and that tractor is still being used twenty years later without leaking or overheating.

I have only been working on old cars since around 1966 so my opinion may differ from others based on their experience. 

Short version.  It still leaks.

1st attempt:

Took out the old stud and replaced it with a brand new one (I bought 2 just in case I had more that leaked)

The engine builder used Permatex The Right Stuff, which had a rubbery texture to it but was in place

I used Permatex Thread Sealant 80633 - coating the threads evenly, stopping at the top of the threads.  This held for a couple runs of 30 minutes or so, then the seeping started again.

2nd attempt:

I removed the new stud and the coolant had literally disitegrated the thread sealant.  I could see it but there really wasn't much left.  I thought I was almost to liberal with it, but turns out not.

So I removed that stud (nothing wrong with it) and tried new stud number 2 (mostly because I didn't want to clean up the one I had just pulled out at that moment)

This time I went with Permatex #2 as outline by many earlier in this thread.

The result, however, is the same.  This time when I start it up it starts to seep BEFORE the thermostat opens.  Once that opens, the seeping stops.  So clearly as the coolant in the block warms up and pressure builds, it pushes through.

I have removed stud number 2 and this time the Permatex was a muddy mess.  I had warmed up the engine to drain the oil (separate project), so the block was still at about 100 degrees when I loosened the top nut.  Right now I have the threads in the block cleaned up as much as possible, but I am essentially back to square 1.

Given the situation, how do you recommend getting down to the threads and cleaning the properly?  I will be draining enough coolant so it isn't close to the stud when I reinsert it, but what tool and cleaning solvent works best to ensure my next attempt has the best chance as possible?

This time I will be using Loctite Head Bolt and Water Jacket Sealant suggest by someone in this thread.

I know it is more expensive, but I have it and the reviews seem to give it as good of a shot as anything else I have tried.

Can someone give me a guide on how much of these sealants I am supposed to be using?  Here is what I'm doing.

Coat my finger and run them over the threads, pretty much leveling it out with them as I go.  I stop at the shoulder of the stud where it widens.  Although on the second attempt I took the Permatex #2 slightly higher.  I then slowly thread it into place - one direction - without backing it out.  I have read that some thread it in, the remove it, recoat it, etc.

With all of the debate about stop leak solutions I thought I would add some dialog from the shop that refurbished my 75 year old radiator for this project.  His name is Dave and he owns DL's Radiator and Exhaust in Buffalo, MN.  He is an expert in my book and owns and works on ton's of these old vehicles.  He said, "I am going to tell you an official radiator shop fix.  Put 2 tablespoons of black pepper in your radiator.  It will not harm anything.  The reason most radiator shops might tell you not to so it is because it works.  I have been doing that on my own vehicles for many years.  There are certain situations that require that kind of fix."

I just thought that was interesting.

On a second, and unrelated note, I have one bolt in the oil pan that is dripping oil.  While I have the oil out, what would you all suggest to seal that up?  LocTight? Permatex #2?