Ryan W:
In my line of work, I use a U Tube Manameter all the time. I have purchased a commercial grade meter (Dwyer 1227).
You can build one with a piece of plywood, some 1/4" polyvinyl tubing, clamps, and a ruler (see attached drawing).
I have taken the drawing in the Kohler Manual and enhanced it. I have added a shut-off valve. (I don't care for that clamp idea).
Build the gauge as noted.
To conduct the test as described, fill the U Tube with water and "zero" out (both legs are equal and at zero). You have two options at this point:
(A) Start engine and throttle to 3600RPM THEN stick the cork wedge into the dipstick tube.
OR
(B) Install cork in the dipstick tube at the beginning. Make sure shut-off valve is in the "OFF" position. Start & throttle up. Once at 3600 RPM, then open the shut-off valve and take your reading.
Either way it will give the condition of the crankcase in terms of Water Column Inches.
I see all these alternative fluids and I guess I don't know why these are being used. Water is the most accurate or an equivalent (Dwyer #A-101 Gauge Oil). For the purist, you can use distilled water for the most accurate reading. Considering the acceptable range (- 5 to -10 WC") good ole tap water will work just fine.