Mark and list,
Diesel engines vibrate in several modes moreso than gasoline engines. (petrol to you lend-lease types:))
What causes pitting and leaks to form in diesels is not clear at first. When you examine the subject in depth, you find the reason to be the vibrations, or more specifically the TYPE of vibration. A diesel vibrates so violently and with such velocity that the cylinder walls in the cooling jacket are actually pulled away from the liquid, if you can picture that. This results in tiny areas of high vacuum, indicated by bubbles. (not air bubbles,, but bubbles of nothing,or at most, a vapor of gasified antifreeze and steam surrounded by the more dense liquid antifreeze. This is called cavitation. The dense hot liquid antifreeze then Implodes as the bubble collapses, hammering at the metal with such violence that a small amount of metal is lost. Each tiny pit eventually becomes a leak. Antifreezes which are certified for diesel use are formulated with a lower vapor pressure, or in other words, they don't tend to permit the cavitation as readily. Contrary to what is popularly bel!
ieved, this phenomenon is NOT corrosion, but it has the same appearance and results. It can be seen to some extent on boat propellors and water pump impellors, as a coarse pitting like you find under rusted steel. The softer the metal, the more the damage. Our listers who are also chemists can advise on specific antifreeze components, but this is the short story. Always use a brand which is certified for diesel use.
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>What's the difference between "good" and "bad" antifreeze, and how do
>I tell them apart? I thought it was just plain ethylene snip snip
>Mark J. Blair, KE6MYK <mblair1@home.net>
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