Can someone please explain how a rusted freeze plug can cause water leak?

And are they fairly cheap and easy to fix?

 

Ok they rust through & leak.

They are cheap & easy to replace.

Now for the explanation & what to do. When a block is machined at the factory, sometimes they don't get all the metal shavings out of the water jacket. This stuff looks like rusty steel wool & collects in the bottom of the water jacket.

Next drain the radiator. As the plugs come out, more coolant will fall on the ground. Try to catch it on crdboard covered with trash bags or rags.

To get the plugs out, tap one side until they pop in or pivot around. Then grab them with vise grips & pull them out.

Now get a garden hose and a coat hanger & pull all the shavings out as best as you can rinse & pull & repeat until clean.
Tap/drive the new plug in with a slightly smaller deep well socket. Same as driving a seal, only these don't stop by themselves. they want to be just a hair or two past flush.

Now your engine will run cooler too.

One more thing, these new ones come in an all inclusive kit usually. Try to use all the plugs they give you. There a re some tiny ones that go somewhere in the heads, but I didn't put them in.

 

Thank you very much for that detailed information.

I appreciate it.

 

When I worked as an auto machinist we used stuff called "Aviation FORM-A-GASKET" on all our freeze plugs, just a coat around the outside of the plug before it goes in. Its just a good safety measure. You can get it at napa and it comes in a little white plastic can, its made by permatex. Its not as rubbery as RTV, but alot more sticky and dries harder. We never installed steel plugs either, only brass, they never rust out.

 

They should not rust if you coolant % is correct. Remove, clean out, and replace as recommended. Make sure to keep your anti-freeze level correct or you will also rust out your steel heater lines and block and you may freeze the block if it gets cold enough where you are.

 

In all the ones I have done, (about four different engines, all Mopar) it was the machining chips/metal shavings that rusted.

Since these were packed up against the freeze plugs, it helped to rust them through I'm thinking.

This job is so much easier if the engine is out of the vehicle BTW.

Be real sure to get those chips out before putting the new plugs in. They really block the flow of coolant.

 

X2 on removing chips

The SBC in my Chevelle was full of chips and cast iron slag in the water passages. Clean out as much as you can!

BTW buckshot500, Where is Clover? Are there any good trails there?