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Old 11-27-2009, 10:59 AM
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bmw_n00b13 bmw_n00b13 is offline
Freude am Fahren
Location: Cambridge, ON
Join Date: Feb 2008
Posts: 6,374
Mein Auto: 99 528iA
Well, for those who, like me, are wondering why they left this hole in the engine, I looked it up on wikipedia. Apparently they're not technically freeze plugs. Freeze plugs are in the cooling system to help avoid cracking of the block if your antifreeze balance is incorrect and the fluid freezes. They need to be there in order to cast the part, and on properly designed engines are, in fact, threaded and blocked with a pipe plug.

Originally Posted by Wikipedia
Core plugs, sometimes wrongly called freeze plugs or frost plugs, are plugs that fill the core holes found on internal combustion engines. The sand casting cores are used to form the internal cavities in the engine block or cylinder head(s), usually forming the coolant passages. The traditional plug is a thin, domed, disc of metal which is pressed into a machined hole in the casting. In some high-performance engines the core plugs are large diameter pipe plugs.
'99 528i ('98/12 build). 282,000km BY29428/Royalrot
Breaking My Wallet since 2009
Mods: Stoptech SS brake hose, 280piece toolkit resting on trunk floor, Beisan VANOS seals, increasing amounts of duct tape and glue
'99 540i (grandfather's)

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