Hot Rods Head bolt on V8 flattie continually weeping

Painted the heads, installed stainless bolts, torqued bolts to 60 and a few will not stop weeping. Any suggestions of how I may stop these annoying leaks?

 

What are you using for coolant? Usually if just water, they will stop.

 

Have you run it and torqued a couple of more times??
Paul in CT

 

I have run it and torqued, and it has 50/50 antifreeze and water.

 

Two things come to mind, you did use a sealant on the studs? Also seems you’re not supposed to clean the threads with a tap. There was a recent thread about both sealant and thread chasing.

 

Use this on the stud threads that screw into the block. I would also use a hardened steel washer under the nuts. 7/16 in. Stainless steel bolts and nuts are not made to withstand the head torque required. Try using correct steel nuts and torquing to 55 foot pounds.
http://www.vanpeltsales.com/FH_web/flathead_cylinderhead_torque-specs.htm

 

Don't seem like much of a leak. If it were mine, I'd leave it alone. Jack E/NJ

 

Standard deal on a SBC block where the head bolts go into the block that is open to the water jacket. Go to your closet Chevrolet dealership parts counter and as for the stop leak tablets. Follow instructions.

 

When applying the silicone on the head bolt do I need to drain all antifreeze...you cant just silicone and put back into the greasy antifreeze filled whole or can you?

 

Use a sealant on the threads.

Always a good idea to clean the threads but, yes, you can seal the threads and put the bolt right back in. No need to drain the cooling system.
But the studs are a different animal. If you can pull the stud and put it back in you can still use a sealer on the threads.

 

>>>When applying the silicone on the head bolt do I need to drain all antifreeze.>>>

Sorry, you can't apply anything to the head bolts in your case. Jack E/NJ

 

I think he may be mixed up on bolt vs stud.
@guy1unico you will have to remove the stud.

 

I have a 454 in my 55 Chevy, and I thought I'd done all the right stuff when I put the engine together by way of chasing all the head bolt holes in the block, using ARP head bolts and ARP thread sealant on the head bolts, but after a while it started seeping a little coolant. With headers and the tight confines I really couldn't tell if it was seeping from a head bolt or if it was a head gasket weeping. Unfortunately, I can't get to most of the head bolts to re-torque them without taking the headers and the roller rockers off which is something I'm way too lazy to do on an engine that otherwise runs great. I tried regular radiator stop leak to no avail but then I heard about K Seal. I bought an 8 oz bottle of it off Amazon (about $14), and that cured it. The stuff claims it'll repair most any crack, leaking head gasket, or weeping head bolt without fear of clogging a radiator and it worked for me.

 

That’s the same as Permatex #2. Been using it since I was a bubble gummer. That and 3M weatherstrip adhesive.

I avoid using any of the silicone gasket makers.

 

If you pull that stud out without lowering the coolant level, it will soon lower itself.

You either need to use some stop leak powder or tablets in the coolant, or do it the right way by resealing the stud with a recommended sealant (not silicone or RTV). I sure hope you didn't clean the threads with a regular tap when you built the engine.

 

As Jimmy and Alchemy said, use the tablets/blocks, and run it a while. My engine man, told me the same thing, and he also stated, "flatheads have the dirtiest cooling system on planet earth" it will seal it's self.

 

The GM tablets are the best fix I have found.

 

Thank you, I will do a combo of the above.

 

Just last night I got my flatty powered sedan out for the first drive this year. One of the studs weeped just like yours, and this engine has been together for over 15 years. I'm not worried about it, as mine usually seal up after a while, and then another might weep a little at another time. I used some Silverseal when we started the engine the first time after rebuild on the builder's recommendation. I did change the coolant once, so maybe I need another can.

 

Here is how I solved my issue...
Bought the Barr's round sawdust pellets. ..2 per gallon of fluid.
Boiled them indoors and broke them down.
Pulled the 2 head bolts covered the threads with black #3 automotive silicone sealer. Shot compressed air into the 2 weeping holes...quickly pushed the 2 bolts into the holes. Tightened the bolts by hand and let them sit for 1.5 hrs.
Then torqued to 60lbs. Started the car 2 days or 48 hrs. later and weeping had stopped cold dead.
Thank you for the solutions that were offered up.
Guy

 

All head bolts on your engine go into the water jacket. Thread sealer is a must. I use Teflon pipe dope (NOT tape) on them and have never had one leak. It also makes the bolts easy to remove next time. Drain the coolant! If you pull any one of those bolts without draining it you will get a hell of an unpleasant shower. Don't forget to re-torque in the proper sequence.

 

Doesn't the center stud go into the exhaust chamber?

 

I use Permatex indian head head gasket shellack on all head bolts, studs. Always seals and will come undone without any drama. Multiple model a and flathead v8s done this way and ive never had a leak

 

Alchemy, It might. I don't have a very good memory these days. However, the same rule would apply