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Old 11-30-2010, 08:54 AM
bluebee's Avatar
bluebee bluebee is offline
Seek to understand,^Value
Location: San Jose, California
Join Date: Mar 2008
Posts: 25,236
Mein Auto: 02 BMW 525i M54 auto 130K
Can you make any sense of this?

To further dig into the inner complexities of the expansion tank, I cut into that incomplete plastic bulkhead separating the expansion chamber from the measurement chamber.

What was revealed confuses me.

Inside was a small rectangular fixed-in-place structure, directly above the distal bottom hose opening, whose purpose eludes me.

This box-like open structure over the distal hose is "pinned" down by a post coming down from the top of the surge tank; and this box has a hole in the top corner of it.

BTW, above all this, there is another hole in the upper neck of the expansion tank. This is where I see water flowing when the auxiliary water pump is running.

Can you make any sense of what the purpose and operation of these structures is?
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