In reguards to Mr. dschwab9's post, your points are understood.
What area of the country do you live in ? and what do you do when
your oil is so hot that at idle the oil light comes on??
with summer temps here hitting 110F almost daily and in the deserts
hitting 120s the heavier oil is what I need.
Mind you I have run the 160F thermostat since the the kick was
a youngin at about 17,000 miles, and have better then followed the
factory service intervals on oil changes of 7500 miles, let the engine
warm a few minutes before running it hard, and now I learn I cut
my engines life short at 250,000 miles, darn guess I screwed up
The important # in motor oil is the first 5-xx this is the flowability
at cold start temps, mind you multi-weight motor oil was designed for
your wife. Start car, 3 seconds, car is in reverse, 6 seconds going 40 MPH
running late for kids to school or going to work, by the 30 second mark
she has hit the freeway, water temp is now a warm 80 degrees and if you
ran straight 30 weight oil metal shavings are merrily working their way to the
oil pan and into the filter from lack of "flow" or volume if you will.
The "tight" tollerances of an engine are in a constant state of change or wear,
altho we hope this is a slow process, the slower the longer the engine will in theory
wear, some wear longer that others, and after the millions of cycles an engine
goes through, in the years of service, many factors pop up, length of each
trip, over all engine temps, hot weather, cold weather starts, road conditions
dust from wheeling, overall average speed (lots of low range driving)
where do I stop, factors all combine over years of service to equal engine
life, no telling how long an engine will last, as these factors are the final
descision makers, we on the other hand need to help these factors be
more favorable to our engines.
Motor oil has the same "thickness" by thickness I mean the physical
size of the oil molecules, don't belive me, use a good micrometer and
measure some different weights, oil has thickness, and is like little
ball bearings in the engine, it keeps one part just away from the next part
to prevent wear, the vescosity (weight) is the factor that determins how
it will flow at a specific temp. 50 weight at 30F is some thick stuff, but
get it hot as in a raceing engine and it provides the nessisary cushon
between high speed moving parts, I don't recommend 50 single weight
oil for a daily driver, as it requires special attention in a cold engine, but
it does have it's place in the lubrication world. Like I said 20-50
HOT!! Weather ,not daily, daily I run 5-30, for the most part, but when the oil is so hot the
cushon goes away, and the low oil light is on at idle, I go thicker.
After all the cushon is gone at such low pressure and it is the flow rate
that keeps the little "ball bearings" in place to protect your engine, like
a wheel bearing race, no race, bearings fall out, metal to metal contact
begins, OK the horse is dead now so I'll stop typing... in a minute,
Bottom line, do what ever you heart want's to, this is America, and if I
want to run 20-50 in the summer it's my God given right golldarn it!!!