"Joe" > wrote in message
news:vRQBg.54586$Lh4.35331@trnddc02...
snip
> However, I've been known to forget to check the oil and on my second tank
> of gas been almost 2 qts low and in total horror! I'm simply amazed that
> the oil pressure light didn't come on.
>

CAUTION - THE LOW OIL PRESSURE LIGHT IS NOT AN OIL LEVEL GAUGE.

While the pressure switch setting of the (well named) idiot light varies, in
most cases it is much lower than the engine requires for extended life.
When the oil level gets low, vehicle motion causes the oil to slosh away
from the pump pickup and the pump can suck up a lot of air and frothy oil.
This air and frothy oil will be compressed and while an oil pressure gauge
may show pressure fluctuations and lower pressure, an idiot light will not
light. As the engine speed increases more oil is pumped to the valve cover
area and drain back slowly allowing the oil level to drop just when the
engine needs it most. Compressed air will keep the idiot light off but is
not an effective lubricant. Low oil quantity will also tend to cause the
oil temp to rise and this will cause rapid oil and viscosity breakdown which
will both cause increased consumption and make the problem worse.

There is only one reliable oil level gauge, it is called a dipstick and it
should be used frequently. I check the oil level at every fueling AND
before AND after any long trip. I have never seen any engine damage or
dipstick failure caused by overuse. Opening the hood will also reveal
unusual oil or coolant blowing around or leaking, and the visible reservoirs
for coolant and other fluids make it easy to check those levels frequently
as well.

YMMV