CMI TSIO-520 and GTSIO-520 Engines
If soon after shutdown you add oil to your engine in an effort to get the oil quantity / level indication back up to the full mark on the dipstick, you will most likely be over-servicing your CMI GTSIO-520 or TSIO-520 engine. In some cases, by as much as 2 quarts.
At such a higher oil level, during your next flight the crankshaft accessory drive gear ( that projects below the top of the oil surface in the oil pan ) will revolve through the surface of the oil and make vapor. The vapor will exit through the oil breather system and be spread over areas of the aircraft.
To avoid such mess and reduce the anxiety of blowing oil vapor overboard, ( concerned that you are using oil ), these six oil servicing guidelines should be followed:
Aircraft should be as level as possible when checking the oil. Use the same level area
as often as practicable when checking oil at your home airport.
Properly install the right-hand dipstick in the right-hand engine, and the left-hand dipstick in the left-hand engine. There is a difference between the two because they are calibrated to allow for the two different engine cant angles.
Note and mark the dipstick's top orientation after properly servicing the engine with a known quantity of oil. Maintain that orientation throughout future oil checks. Readings
can vary by as much as 1/2 quart simply by having the dipstick's orientation 180° in error.
Calibrate each dipstick. Immediately after draining the oil completely, add back your normal operational quantity of oil. For example, 10 quarts. Insert the dipstick and note the oil level indicated. Often off as much as 1 or 2 quarts, the dipstick may indicate 8.5 quarts. In the future, remember that such 8.5 quarts level represents the 10 quarts level.
Measure oil drain-down quantity. Do so by measuring the oil quantity immediately after shut down, then again 12 hours later. Note the increased indication of oil level after the
12 hour period -- typically due to oil draining from the oil filter, the oil cooler and the
engine oil passages.
For long flights, especially over water, service the engine to its full capacity. Knowing that at full capacity some oil will be blown overboard, expect to wipe off the airframe accordingly without becoming anxious about seeing excess oil.