Those are the round circular discs around the bottom of the engine block. They are also called core plugs. There is one right behind the motor mount, just so you'd know what to look for.

I believe the freeze plug name comes from the idea that were your coolant ever to freeze in the block, the plugs should get pushed out due to ice expansion before the block is cracked. There are small ones on the back of your cylinder heads as well.

They come in two flavors: zinc plated steel, and bronze. Bronze resists corrosion better, but are more expensive. Guess which ones Chrysler went with?

 

NEVER use radiator stop leak, or any magical stop leak product, NEVER. If have a leak then fix it right, you will more harm than good using that stuff, I destroyed a radiator and a water pump using that crap.

 

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Ok, thanks for all the info guys!

 

Well Jack, I used the radiator stop leak cause I did have freeze plugs in the back that were leaking and impossible to get to without jacking the engine out. I flushed my kit put it in ran it and let it sit for awhile then drained and replaced coolant. I was about to replace plenum, water pump, thermostat,timing chain, all radiator lines etc. So i wasnt worried

 

Also called expansion plugs. They are brass, or, more often.... steel plugs that are press-fit into holes in the side/back of the engine block. The idea is, if the coolant should freeze (and thus, expand....) the plugs will blow out first. In reality, it seldom happens that way, and the frozen coolant will expand to the point that it starts cracking the block....... There ain't no fixin' that. Time for a new one.

 

while the name freeze plug is because people assumed they'd push out if the coolant were to freeze that is not the purpose of them, and you'd be lucky to not crack the block. core plug is more accurate since they are in the block to get the sand out after casting.

also did anyone ever see the myth busters where they tested some auto myths, one i remember they tested that worked for them was using an egg to stop a leak, as in cracking the egg and putting the yolk and whites into the radiator.

 

That would be an emergency fix only, the problem with those stop leak products is it thickens when mixed with water/coolant and coats the inside of your system and plugs holes, when it gets hot it hardens. The problem come in when it basically gums up every thing and can cause blockage and cause even more issues than you started with.