Head Bolt continually weeping

19Fordy said:
rockfla is 100% correct about not using stainless nuts and bolts as they shear too easily using the torque required on head bolts. The threads will stretch, especially after repeated use.
Click to expand...
Industrial fasteners being my business......I have had long conversations with an associate who helped write both SAE and ASTM fastener specs and has forgotten 3X's as much I have known about Stainless Steel. He said "nuts" are not as critical as studs and bolts....They get a good amount of "work hardening" when they are made.......He has done many pulls on SS nuts to as much as 120,000psi .........BUT That is not normal and NOT the norm for Stainless fastener industry in general!!!!! Again, I would not trust any SS fastener for something as important as a head stud, bolt or nut!!!!! Since he has already pulled 60 and NOT stripped a bolt (or in this case a nut) certainly lends itself to "work hardened".........still I would not trust it!!!!




Also let me preface my comment to "commercially available" Stainless Steels which in my case would encompass 303, 304, 305, 307 OR more commonly the all previous mentioned into 18-8, 316, 316L B8 and B8M. There are a few who sell a "strain hardened" Stainless and IF that is what was used then my platitude is null & void.


Also, just at a quick glance those appear to be a "finished" pattern nut and NOT a "heavy pattern" nut as well, "IF" so.....Another NO NO. They were and NEED to be of the Heavy Pattern!!!!
 
Last edited:
Another possible side effect of torqueing that much might be thread galling and filling stud threads with SS. Might be hard to back them off now. Jack E/NJ
 
It'll stop at some point. If you want pull the offending stud and put some anti seize on the stud and reinstall. That'll work also.
 
Tinker said:
It'll stop at some point. If you want pull the offending stud and put some anti seize on the stud and reinstall. That'll work also.
Click to expand...

Very difficult to pull the studs without removing the head first. As I (and others) have stated, better to just wait it out or add a sealant to the cooling system.
 
JSeery said:
Very difficult to pull the studs without removing the head first. As I (and others) have stated, better to just wait it out or add a sealant to the cooling system.
Click to expand...


I didn't say you wouldn't have to remove the head to get to the stud.
 
You could probably also just put some rtv sealant around the stud and put the nut back on. As I agreed above in my original post, I'd just leave it alone and it'll most likely seal it's self over time.
 
The studs appear to be normal, the nuts appear to be stainless - so you'll need to replace them. You might look to McMaster-Carr - they have high quality Grade 8 nuts that are zinc-aluminum coated so they don't rust and will look correct on your engine. They cost about $8 a box of 25.

https://www.mcmaster.com/93827A241/

On the leaking studs: If you're willing to pull the heads, then you can use a stud sealer on the coarse threads. I use a teflon type product from ARP. I don't like to get water between the studs and the heads - causes rust, so I prefer to fix the problem at the source. ;).

Other than that method, you can try something like Moroso Ceramic Seal - really good product. Make sure you follow the instructions carefully - especially related to draining and flushing the system and filling with WATER before you put this stuff in.

https://www.moroso.com/ceramic-engine-seal35500/
 
In my experience, stuff that leaks doesn't generally stop leaking on it's own. I've had the same issue, I've taken the offending nut off, slopped on some permatex teflon thread sealant on the stud, then re-torque that nut and it worked great.
 
You really need to seal the threads on the block end of the studs. Otherwise the studs and nuts will corrode over time and make those pretty painted heads look bad.

It also looks like some of the studs are not fully seated. The nuts should be near flush to the top of the studs, like in this photo of my '34 motor.

nuts.jpg
 
Last edited:
Upon closer viewing of the last picture, the nuts looks like Cadmium plated - so they may be just fine. Take a magnet to them if you're not sure - most stainless is non-magnetic.
 
I don't think it's the same engine or nuts. Just an example of how the nuts should be nearly flush with the top of the studs. The nuts in the last picture look more like grade 5 galvanized to me. Jack E/NJ
 
Not sure what thread seal you used but Permatex non hardening works well but that horse left the barn so Aluminum powder Alumaseal or copper powder sealer both work well in this situation. The leak doesn’t look too bad & either will do the trick by filling the area leaking, in your case probably not enough sealer on that one studs threads.
 
Just an observation but if I wanted to remove just one stud, providing it had been fitted relatively recently, I would use a variation on the double nut method.
Use a long connector type nut, and screw a bolt down the end to lock them together. Then, hopefully the stud may come out unharmed.

If you have a spare stud you could also weld the nut on the original and get it out like that.

Then apply sealer of your choice and reassemble up. It might be worth leaving it a little while before putting the coolant back in.

Mart.
 
Had some weeping between head & block. Changed 16# radiator cap to a 6# and 6 oz Bar's Leaks Radiator Stop Leak. Leak stopped.
 
I think he fixed it. He hasn't been back to this thread since April 25. He was here yesterday when he was looking for some parts.

I always appreciate it when someone comes back ands let's us know how everything turned out.
 
You must log in or register to reply here.
Back
Top