Re: manifold casting plugs?
Just curious as to why you all say no to silicone and even call it silycone, I know if you overdo it chunks can break loose and wreak havoc on oil pumps, impellers, block passages ect, but it is waterproof and good for underwater applications as well as high temp, heck you can apply the stuff directly to exhaust headers and it wont burn off so what gives?
There's a pretty good bias against silicone (RTV) here because a lot of boat owners tend to assume that it's a good marine sealant. It's not, but they don't know that, so it tends to get used to keep water out everywhere, and does a rotten job.
On my boat I had to clean it out of the drain plug hole, all the through holes for instrument wires, the dump for the bilge pump, and around windows and hatches... all because it wasn't sealing any more (it typically lasts something like 1 season). I replaced it with 3m 4200, which is a marine polyurethane sealant.
Others here can tell you why polyurethane is better than silicone for marine sealing.
I did use high temp RTV silicone to seal some engine gaskets, because that's a good use for it. You could use it for anywhere you need a seal on a high heat component, really. But it's a far better idea to just make sure the freeze plug or whatever fits right in the first place.. and if it fits right, why use silicone or another sealer at all?
Wouldn't you rather know if the plug is corroded so you can replace it, instead of getting a false sense of security?
So there are a few uses for silicone, but most folks on this board have run into it being used wrong enough times to hate it
Erik
