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Old 10-15-2008, 04:23 PM
desertdriver desertdriver is offline
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Quote:
Originally Posted by raleedy View Post
All of that palaver might be true if it were actually "oil" we were talking about, but BMW engines are not lubricated with "oil". The lubricant is not especially viscous when cold. Moreover, cold engine parts are smaller than warm ones. As a result, there's no special thing about low operating temperatures that would inhibit lubrication of engine parts, and the engine will accept normal operating loads when cold without damage. The oil temperature gauge does not help with this because its cold peg is at 160 degrees -- the internal temperature of well-done meat. If the gauge serves any useful purpose, it is to flag high operating temperatures, which are detrimental to both the lubricant and the metal engine parts.
Dont confuse yourself with the synthetic vs petroleum oil arguements. Its all about hydrocarbon chain length and its relation to temperature dependent viscosity. All synthetic oils are hydrocarbons, just like petroleum based oils, they just have different polydispersity(better in synthetics). Think like a scientist not a lawyer. Molecular physics is molecualr physics, whether you pull the molecules out of the ground or synthesize them in a lab or plant the behaviors are consistent. the greater polydispersity of the mineral oils make them a bit better at lower temps.


Here is an article that compares the two if you care to read it. The (petroleum based)mineral oils actually lubricate better at low temps(thicker film before parts expand). this means that its even more important for synthetics to warm them up. Yeah, I used to be a metallurgist, so I know about expanding metals.

http://www.machinerylubrication.com/...?articleid=586

Last edited by desertdriver; 10-15-2008 at 04:40 PM.
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