Technical Sealing flathead studs

My car has suddenly started weeping coolant out of the head studs. Quite a few of them, as a matter of fact. I had a teeny tiny bit out of one or two in the past, and didn't think much of it. ARP studs were sealed with Loc***e Teflon goop when I ***embled the engine.

I don't want to make a habit of re-doing 48 head studs on an annual basis. Especially not with multiple retorques after heat cycles.

After a search and reading through here, [https://www.jalopyjournal.com/forum/threads/flathead-head-sealing.334374/page-2], I've got some Permatex #2 and ARP beveled washers, part #400-8539. What I'm not certain of is the corresponding O-rings to use. I bought a handful of 7/16" ID Viton O-rings from Amazon, and they don't seem to fit very well.

If anyone has successfully used the O-ring washer method, any recommendations on O-ring dash number, dimensions, or a part number would be very helpful and greatly appreciated..

Thanks

 

Try Water Gl***. Follow the directions. Worked very well for me.

 

Henry Tapped the original head bolt holes with a slightly undersized tap so as to have them a tight fit on the studs to forestall what you have. Most likely somewhere along the way someone used a normal tap to clean the holes and now they're a bit too loose.
ARP has some thread seal loaded with teflon and other solids that may be your best bet unless there are studs with a slight oversize available.

 

I had mine tin plated from the bottom of the fine thread , all the way down. It tightened up the clearance nice andshould make head removal easier.

 

Anaerobic pipe sealant works wonderful on this type of seal .

 

Before you take anything apart, try a bottle of Barsleak in the radiator.

 

Bars Leak is good ****, just might work, worth a try.

 

Has anyone ever tried br*** washers under the nuts on the top of the head?

 

Br*** washers or O rings won't work unless they can seal up tight in the threads of the stud. That water is creeping between the stud and nut, so it is finding a very slim path. I used the stinky brown permatex, and still had a few weepers. My machinist recommended SilverSeal and it did the trick.