When sealing head stud/bolt threads..
Mistake? If so should i use something else by pulling one stud at a time , applying X and retorquing ?Engine is on the stand still
Upon redoing headgaskets on that setup (thought there was an issue that didn't exist) I ended up using teflon tape applied properly (ie, twisted in the proper direction to prevent unwrapping while installing) and applied thickly after I chased all the threads in the block. Using teflon tape it has not leaked either. The negative to teflon tape is that in the future if you need to pull the studs you run the risk of getting tape fragments in the cooling system where you could end up plugging up a little of the radiator or the heater core, but, on a car with head studs, unless you are doing a complete rebuild where stuff in the coolant wouldn't matter, how often are you going to be pulling the studs out of the block even if you have to redo the headgaskets? And, yeah, pulling the top 4 studs is a little different since the bottom of the studs are either blind or with only a small amount open to coolant, not a full open hole like the rest of them on the deck, so again, I consider it a non-issue.
Now on headbolts I would use nothing but ARP thread sealer. Never had a problem there either.
Also, I have gotten in the practice of putting a couple of GM sealing tabs in any of the setups I do from now on. Good insurance and saves headaches.
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Personally I use the Permatex Ultra series.
On studs, I fill the bolt threads & screw them in, then wipe off the excess.
It works fine.
Personally I would not trust teflon tape, it is designed for close tolerance pipe threads. You would have to put a ton of it on to even come close to sealing up regular threads. While it may have worked, I would never recommend this.
SRS, nothing but proper torque to keep the bolts and caps in place.

I have personally used RTV (ultra black) and ARP thread sealant and have never had a problem with either one.
I'll take a locked stud over a leaky one, considering I have been down that road and it works. I'll stick with it.
The problem with RTV is if you let it set before you torque down the heads you have teh possibility to cause the RTV to shift in the threads when they are torqued, which can cause a leak as well. I know a few instances personally where that has happened and the builder always torqued the heads after the RTV has already setup for a day or two. The other big issue with RTV is if the threads on the studs/block are not fully clean of dirt and oil then you will not get a seal. Eassy enough to say you made sure it is clean, really hard to be 100% certain.
Paste sealers, like ARPs or Permatex non-hardening stuff, is made to deal with less than ideal situations in regards to cleanliness and such and usually do a good job while sealing. Only if the space between threads is too great does it become a compromised solution. That is when something that fills the gap more "solidly" such as teflon tape wrapped on heavily does the job. You just need to make sure it is wrapped in teh proper direction to make sure it does not unravel when you install the studs into the block.
As I said before, GM actually calls for using it's sealing tabs in ALL applications which have either bolts/studs go into water passages or those applications that have aluminum castings holding back cooling system pressure (such as waterpumps and blocks). They are extremely effective on making sure you don't have leaks/weeping from bolt/stud threads and/or porous aluminum castings.
Northstar blocks are well known for having the possibility of leaking through proous castings to the outside of the block itself. Since the LT1 has both bolts/studs the protrude into the waterjacket as well as aluminum waterpump and heads, it falls into all catagories where using sealing tabs in a requirement.









