Freeze Plugs

Brian,

On my SD240 one block plug is leaking , can you give advice on
replacing. Easy way to remove?
Have an idea but any help is appreciated ,

I need to measure it for sizing.

Thanks

Depends on what you have for access.
If you have a lot, drill and use a dent puller to yank it.
Most times you don't have the access for that, so drill and put a sheet metal screw in it and take a pry bar to pop it out.
You can also drill and put a punch through the hole and lever it out with that.

Depends on what you have for access.
If you have a lot, drill and use a dent puller to yank it.
Most times you don't have the access for that, so drill and put a sheet metal screw in it and take a pry bar to pop it out.
You can also drill and put a punch through the hole and lever it out with that.

I will go with the sheet metal screw , wood block for lift and that will work
thanks much!

1-5/8"

1-5/8"

Thank you !

Those plugs are core plugs. The original holes were places where casting sand could be removed from the engine block. It was a stroke of good luck if the plugs often were pushed out by expanding frost, allowing the water to escape and hopefully save the engine.
There is a rubber like material sandwiched between two metal washers. The contraption was fitted in the core plug hole and tightened, forcing the rubber to expand and seal the hole. I would rate this as a temporary fix. Make sure you apply Permatex Aviation Form a Gasket to the mating surfaces of the block and the new metal plug.
https://www.permatex.com/products/gaske ... uid-16-oz/

Those plugs are core plugs. The original holes were places where casting sand could be removed from the engine block. It was a stroke of good luck if the plugs often were pushed out by expanding frost, allowing the water to escape and hopefully save the engine.
There is a rubber like material sandwiched between two metal washers. The contraption was fitted in the core plug hole and tightened, forcing the rubber to expand and seal the hole. I would rate this as a temporary fix. Make sure you apply Permatex Aviation Form a Gasket to the mating surfaces of the block and the new metal plug.
https://www.permatex.com/products/gaske ... uid-16-oz/

Will do , thanks Friend

Stay safe!

To expand on Nikki's comment about them being "core plugs" not "freeze plugs". That is 100% correct, you'll not find them on castings that have an opening to remove the core sand. That includes wet liner engine and ones with an open deck like the Detroit 8.2 and many imports. Castings with enclosed voids, need a way to get the core sand that form the void in the casting out, once the casting has cooled. Rough holes are left, than machined to take pressed in covers to seal.
Often you can see the remains of rods or "struts" that help hold the sand in place, but can not be removed, still in the head or block, they often become part of the cast wall at both ends.
Good casting is an art, and mold-makers are highly skilled. Take a cylinder head for example, making the mold for the intake and exh passages doesn't seam too hard, but making the coolant passage that must surround the other "voids" but not connect to them is a real art.

Having seen the inside of a foundry wood working shop and known a designer for the castings and plugs, I would wholeheartedly agree that it’s an art. One that doesn’t get much recognition.

It is something most of us take for granted, but to do it well is very hard. I shop class we all got to "ram up" one mold and make the pour. (aluminum) and that was enough for me to know I'd never be good at it.
I'm sure they get one mold made up to spec's and a day later the engineer comes back and says "we need the coolant passage changed"! I wonder how many mold makers are bald from pulling out their own hair?