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Old 01-23-2005, 08:38 PM
phlsteve phlsteve is offline
Officially Welcomed to the 'Fest
Location: Philadelphia, Pa.
Join Date: Jul 2003
Posts: 49
Mein Auto: 2002 325ci
Cool Skeptical me...

Originally Posted by wingspan
I'm sure the dealer would be happy to fill it up for you, but why not just put in the recommended fluid mix (i.e. water/antifreeze) to top it off yourself...
My dealer told me to simply add water. Since the concentration of the antifreeze from the factory protects it to crazy cold temps, a little water wouldn't dilute it too much. I ignored him, of course, and bought some good Prestone pre-mixed anti freeze. It was pricey, but worth the peace of mind. Ended up needing close to a half gallon of fluid.

Two dealers told me two different stories about why this happens, btw... One told me that the water in the antifreeze mixture is released a little bit at a time through a pressure release valve, causing the level to eventually drop. Another dealer told me that the water pump uses the antifreeze as lubricant, which eventually causes antifreeze loss. I don't believe either of these stories.

I've never before had a car that lost antifreeze (but all my past cars have been acuras, so of course not). As far as I knew, the antifreeze overflow tank is what deals with the fluid expansion. And I can tell you for sure that water, mixed with antifreeze or not, is a horrible lubricant, so I don't buy the water pump story either.

I'd love to know the real reason why this happens.
Phila, Pa
Steel Grey '02 325ci, SP, PP, HSeats, HK, Xenons
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