I have had all the freeze plugs on my 1999 Jeep Wrangler replaced, now the one near the fire wall started to leak. My mechanic said to use Alumasealto fix the problem. my concern is what other things it may plug up
I’d be better to replace the freeze plug. A stop leak product might work for a while. But if the freeze plug is leaking because of corrosion, it could blow off the engine at any time dumping all the coolant on the road.
Your mechanic does not want to re-do that one, so if you take it back to him, he will probably put Alumaseal in it and tell you he fixed it.
Is the leak small, or are you loosing appreciable amounts of water? If the leak is just a stain down the block, Alumaseal might be a permanent fix.
I used a more aggressive sealant to seal a head gasket leak once. Head gaskets are tough to seal. It stopped the leak for a couple of years, but when I finally pulled the head to replace the gasket, I discovered that the sealant had built some nasty obstructions in the water passages in the head.