Re: how much to change the oil

[Mike Orth <ORTHM@xxxxxxx>]

In all of this talk about how oil change intervals effect engine life,
I've seen little mention about how much proper engine warm up has to do
with engine life.  I think that has more to do with engine life than if
I change oil at 3k miles or wait till the little lights say its time.  I
don't care how often you change the oil or what oil you use, if you do
redline shifts on a cold engine, you're going to cause problems.  Engine
parts expand as they warm up and the tolerances between them will get
tighter.  So while the engine is warming up, all those parts have a few
more thousandths of an inch to bang around in.  Now add in the fact that
the different metals used expand at different rates, some gaps must be
made larger when cold so that the parts will move properly when at
operating temp.  According to my guages, it takes the oil about 10
minutes to get up to normal temp.  The water temp comes up in about 5.

Having the oil at operating temp also helps to evaporate water that may
collect inside the engine from condensation that builds up during the
colder times of year.

Mike Orth
Tarheel Chapter

88 325is - Track car with 182K miles and still running strong
93 325is

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