Van's Aircraft RV-12 Pilot Operating Handbook page 29

Date:12/03/14 Revision:3
Little or no oil pressure is usually caused by a failed pressure
relief valve, pump, loss of oil, high oil temperature or a defective
gauge. A landing should be made as soon as practical using
minimum RPM changes. Plan a "Precautionary Landing
Approach" as complete engine failure is possible at any time.
NOTE (SkyView Only): Zero oil pressure will be indicated if
main bus power is removed.
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RV-12 PILOT'S OPERATING HANDBOOK