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Old 10-15-2008, 01:55 PM
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raleedy raleedy is offline
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Location: Oregon
 
Join Date: Sep 2007
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Mein Auto: 2013 F10 528i
Quote:
Originally Posted by desertdriver View Post
the most critical apsect of warmup is the oil temp. this is because oil viscosity changes with oil temp. When the oil is cool, it does not lubricate your engine properly(its too thick), especially if you run it hard. BMW's use of the oil temp guidelines will help your car last longer by preventing you from running your engine hard under substandard lubrication conditions. With an engine that has such close tolerances(any finely engineered powerplant), the oil must come up to a sufficient temperature so it is not too thick to lubricate properly. Kudos to BMW for using a better way to help you take care of your car. If you ignore their recommendations, the risk is higher engine wear and shorter engine life. If you live in temps near freezing, it can take 20 mins or more to warm up your engine to the optimal operating temperature needed to run it hard if left out overnight.
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.
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