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Old 06-22-2010, 12:19 PM
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bluebee bluebee is offline
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Join Date: Mar 2008
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Quote:
Originally Posted by doru View Post
There was a thread a looong time ago (maybe on another forum) with the dissection of one of those expansion tanks. The mechanism that holds the combo together crumbles over time. The first sign of a crumbling float-dipstick is the dipstick is not straight anymore
Thanks for the clarification!

While I don't profess to understand the seemingly redundant level-sensing mechanisms yet (I will eventually), I think I have the basics now:
- The post & float assembly are part of the expansion tank and can't be replaced independently of the expansion tank.
- The level sensor is (somewhat) separate and can be reused when replacing the expansion tank.

Digging for that dissection post you mentioned, I found one with great pictures that intimates the separate post-and-float mechanism somehow actually interacts with the electrical level sensor mechanism!

I don't profess to understand this yet, but, is this that post you noted?
BMW E39 Expansion Tank Failure Analysis

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Attached Files
File Type: pdf E39 Expansion Tank Failure.pdf (695.4 KB, 429 views)
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