Weeping head gasket- fresh rebuild
 

I have a freshly rebuilt stock 59-AB in my ‘46 Mercury, and it’s leaking coolant between the head and block on the driver side down low above the exhaust manifold. The leak is slight… things are dry when the engine is off and cold. But when I run it up to temp for 5-10 minutes and build some pressure, the gasket surface is wet an inch or two along the block/head interface. I’ve checked the torque and nothing has changed after a couple cycles. I’m assuming I’ll just watch it and check/retorque a few more times. I had good results with a head gasket sealer on a modern car, so I may entertain that if the leak continues or worsens. Any preferences on brands for flatheads? I’d like to avoid replacing the head gasket for now. Thoughts welcome. Thanks

Re: Weeping head gasket- fresh rebuild
 

What type head gasket are you using?...

Re: Weeping head gasket- fresh rebuild
 

I talked to the rebuilder and he used Felpro gaskets, and stated that they have an adhesive that requires a few heat cycles to fully activate. The block was decked and the heads were milled, so he’s thinking to run it some more and see if it cures itself. He recalled the heads being fairly corroded, though, but they looked pretty typical to me.

So my plan is to wait and see before doing anything. He did mention that he’s heard good things about Blue Rhino sealer if it comes to that.

Re: Weeping head gasket- fresh rebuild
 

Maybe he meant Blue Devil

Re: Weeping head gasket- fresh rebuild
 

Bruce, for what it's worth.... I have always used Best Gasket GraphTite head gaskets. So far so good. I have had the common stud weep problem and they sealed up. You went through all the right rebuild procedures, I would be suprised if you have a lasting problem.

Re: Weeping head gasket- fresh rebuild
 

Do you have to run it with a pressure cap?

Re: Weeping head gasket- fresh rebuild
 

My first thought was to tweak the cap so that it doesn’t hold pressure. I have an original cap that the relief spring has frozen/rusted, so may use it for mods. Thanks

Re: Weeping head gasket- fresh rebuild
 

Have you check the torque on the nuts yet? If not, do another tightening sequence on both heads. Sometimes they loosen up a bit after a few heat cycles after a rebuild.

Re: Weeping head gasket- fresh rebuild
 

See post #1

Re: Weeping head gasket- fresh rebuild
 

Check the torque at operating temper

Re: Weeping head gasket- fresh rebuild
 

Ah. RIF. Reading is fundamental. LOL! Missed that in the original post.

After re-reading, I did notice another tidbit that was mentioned. Where was the corrosion in the heads that the builder noted? In the coolant holes or on the face of the heads?

Re: Weeping head gasket- fresh rebuild
 

That's why I like the GraphTite gaskets with a good coating of Copper Kote.

Re: Weeping head gasket- fresh rebuild
 

Metal gaskets with copper coat semi set and torqued cold and hot have always worked for me. The other gaskets are a bear to clean off if you have to pull the head.

Re: Weeping head gasket- fresh rebuild
 

Many people use Copper Kote and it's a great product. Just understand that is is a type of glue and it's quite a chore to removed if needed in the future.

Re: Weeping head gasket- fresh rebuild
 

Also, correct. You will need new head gaskets if you try to pull the heads back off. Head gaskets are expensive.

Re: Weeping head gasket- fresh rebuild
 

You might try the old solider seal. I have used it many times with good results

Re: Weeping head gasket- fresh rebuild
 

I use a tube of AlumaSeal. Maybe it is the same as solder seal. It won't clog anything.

Re: Weeping head gasket- fresh rebuild
 

If it were me, I'd use the latest hi-tech sealer available. Chemistry has come so far lately that the "old reliables" are passe'.

Make sure the block is clean-clean-clean and follow the instructions exactly.

Re: Weeping head gasket- fresh rebuild
 

Even though the block and heads were machined I'd still double check their straightness with a machinist's straight edge lengthwise and diagonally across the block and the head to check. Then I'd pressure test it so you can see where that water is coming from. I bought all that testing equipment to check the blocks before I do anything to them.

Re: Weeping head gasket- fresh rebuild
 

I have had good luck with this head gasket & block sealant in an off topic suv. Has some type of mil spec fibers in it.