Hot Rods Brass or steel pipe plug?

In all my years of wrapping Teflon tape around threads, I don't remember every having had one leak. When I replaced the intake manifold gasket a couple years ago on my SBC I put a chrome looking Allen head plug in that little 1/2" hole by the thermostat housing because it was low profile. For whatever reason it started leaking over the winter.

Since I hate disturbing antifreeze and don't want to have to drain it again I figured I'd find out if I shouldn't be using that chrome looking plug, for whatever reason. Should I double wrap it or use some kind of thread sealant?

 

all I know is that sbc chromed t-stat housings leak more often, some even have an o-ring instead of a gasket so if you have one "chromed or not", but do have a chrome plug? maybe the issue is the plating?

you can use a vacuum on the rad opening, then pull that plug ...hydraulic systems guys working on heavy equipment do that when changing a hose.. putting a vacuum on the hyd tank

 

Lately I have been using the paste type thread sealer the pipe fitters use. I think works better then the teflon tape.

 

Chase the threads with a tap, or you'll probably get to do it one more time ... I'd find a square headed iron plug, not trusting anything chromed around antifreeze. Permatex 3H is still my choice if using anything. Also, some of those allen headed plugs don't have any taper.

 

I always use this.......

 

Just be careful when using any kind of Teflon especially the paste with tapered plugs in any kind of castings as it acts like a lubricant and it’s very easy to over tighten the plug and crack the casting. Come to think of it take a closer look at the intake and make sure that’s not what happened. As for chrome I try to stay away from it concerning pipe plugs. I will usually try to use anadized


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Thanks guys. I think the comment about the Allen head plug not being tapered was the key- it wouldn't get snug. I bought a brass plug with the square head and it sat too high for the water neck so after a little trim job it fits fine and snugs up, so I went back to my old favorite- teflon tape.

Thanks again.