Freeze plug fell out

[Highbanked Hauler]

     I DEFINITELY drained  my "spare" 440 last fall so I know it didn't freeze up but the middle one of the big plugs on both sides of the bottom row came out. Now it has gotten cold but not by northern standards and these are steel plugs not brass so I am wondering if steel contracts more than cast iron does ? Any other ideas ?

[moparnation74]

I have always used brass.

Two reasons.

1.  Less corrosive than steel plugs

2.  Softer metal than steel so they can perform their purpose effectively if needed.  To limit damage to the block during severe winter weather.

[ws23rt]

     I DEFINITELY drained  my "spare" 440 last fall so I know it didn't freeze up but the middle one of the big plugs on both sides of the bottom row came out. Now it has gotten cold but not by northern standards and these are steel plugs not brass so I am wondering if steel contracts more than cast iron does ? Any other ideas ?

The difference in expansion/contraction in the steel plugs vs the cast iron block is so small that it is not the reason they fell out.
Most likely corrosion did it. When steel develops rust that process has an expansion component. It also makes a crumbly not so good sealing surface. Over time those plugs are only held in by rust and the compression stress of the initial installation has been relieved.

[fy469rtse]

yep put brass ones in,
but watch out for the cheap ones , not enough material to the sealing sides, look for originals , do not get them from 440 source or similar , sides should be deep , its whats wrong with a lot of the steel ones also, seal them in as well , gasket goo , whatever you like to use , 

[Wicked72]

+1 for brass