Oils and how they work

Some interesting opinions on old wives tales about oils.
The Warmup Myth:

Warming an Engine up at idle and with no load is a great way to contaminate the Oil and gum up the Piston Rin Grooves. One
problem is that the Compression Rings are insufficiently charged to gas pressurise properly. This makes it the ideal time
for Oil/Fuel/Water/Carbon deposits to collect in the Piston Ring Grooves and destroy the Piston and Piston Ring Groove's ability to manage the combustion charge properly.
Much has been published about this under PCV. Start the Car and drive off moderately, avoiding full throttle until
normal temperture shows on the Temperature Gauge.

The Cold Starts Wears Out Engines Myth:

Look around the wrecking yards at any pulled apart Engine and you'll see Oil all over every internal part.
The Crankshaft Oil ways and Engine Block Galleries will be full of it. There's no reason to assume
that a high degree of wear will occur on an Engine during a cold start.
The amount of Engine wear sustained from a Cold Start is tiny. The apparent cause of Engine Wear from
a Cold Start is caused by Warming Up as mentioned above. Gummed up Piston Rings is frequently mis-diagnosed
as worn out Piston Rings, Bores and Pistons when in fact short runs and warming up has filled the Piston Ring
Grooves with carbon and defeated gas pressurisation of the Compression Rings.
[edit] Don't Overrun the Oil Change Interval:

By the time the Oil shows as black on the Dipstick, an Oil Change is overdue. By this stage the Oil will be
full of contaminants and to some extent have lost its lubricational abilities. While this Oil can be recovered
by a refinery, there's no practical way to recover it at home.
Dirty Oil will layer the Engine with Carbon and discolour the surfaces. The small amounts of carbon in the Oil
will accumulate in corners of the Galleries and in the bottom of the Valve Lifters.
Changing the Oil when it's required and keeping the Oil clean is one strong factor in achieving maximum Engine life.
[edit] Short Runs:

The short answer is, avoid them.
Cars that do a lot of short runs suffer from Oil Dilution. Every Cold Start puts Water and Fuel into the Sump.
The Engine is dependent on hot runs to make these additions evaporate out. If insufficient hot running occurs,
the Engine Oil Level can appear to remain steady or even rise. During the first long hot run, the water and fuel
will evaporate off. Subsequent checking of the Oil Level will show that the level has dropped drastically.
All Engines burn Oil. Excessive short runs can mask this fact.
If you are forced to make short runs, offset them by making longer runs that heat the engine to normal temperature
for an hour or more. This is part of the same program that will give you the longest Engine life.

Engine Oil can take up to 20 mins to reach a temperature high enough to evaporate out Water. If the Engine Oil does not become hot enough deposits of emulsified Oil and Water will develop within the Engine as the photo with the Oil Filler Cap removed shows.
[edit] Short Runs:

Red_Devil