Head studs leaking coolant

[BillK]

Tim,
I use the Permatex White Teflon sealer, only because its a lot less expensive than the ARP stuff.
That being said, I have found that the trick to getting studs to seal is to put a healthy "glob" of the sealer in the hole in the block before you thread the stud in. I also put some on the threads of the stud, but not a whole lot. I think what happens with studs is for some reason if you only put the sealer on the stud, 90% of it gets wiped off as you thread the stud into the block. I don't understand why the same thing does not happen with bolts, but ever since I have started putting the sealer in the hole first, I have not had an issue with the studs leaking.

Hope this helps,

[Tim H]

Thanks for all the suggestions thus far ... I can't get back at it until this weekend. Work gets in the way sometimes. Going to do a very careful disassembly and see what we can determine.

[Rich Biebel]

Permatex brown #2 or Indian Head Shellac.

Messy but works.....threads need to be reasonably clean.

Put it on the nuts up top as well....

Use laquer thinner to clean the stuff off.

[KennyAnderson]

Hold up on dat carwash genta-men! Ran into this issue on one of my big inch n20 motors. I knew the heads were torqued correctly as I could see the "crush" on the copper head gaskets. If you are sure about the torque on the heads and have no fastener issues, go get yo-self a bottle of Moroso ceramic block sealer and follow the directions. Easy and solid fix to a common problem.

[MAURICE BLENDHEIM]

Tim…Try Aviation PERMATEX, make sure the threads are dry...problem solved. MB.

[larrylomascolo]

I m just wondering why studs instead of bolts on cast heads,bolts seal 99.9 percent of the time

[Tim H]

Engine had studs before I bought it and we replaced them with new ones as part of the freshen process. Block is fairly old (30 years approx) and compression is 13 to 1. I do recall a pile of black silicone type sealer on the old studs and some of the threads were in tender shape so we chose studs in an attempt to preserve block and apply that "more even clamping force" that studs offer. Unfortunately coolant got into the oil and now it no longer turns over smoothly. It is out of the car and partially apart,pushed to the side and my old reliable but tired 468 is back in. Just got tired of wrenching on this 496 and want to go racing before our season is over.I think block could use heli-coil inserts for most if not all the head bolt (stud) locations.