since 1940

High oil pressure in Lycoming or Continental Aircraft Engine

A. Oil relief valve improperly adjusted.

B. Improper oil weight. This is the most common reason for high oil pressure in cold weather.

C. Plugged oil passage in Lycoming engines. There are three holes on the oil screen or filter adapter pad. The center hole goes from the pump. The left hole is the return from the cooler. The right hole feeds oil to the engine after the oil goes through the filter or screen. If this passage is restricted, either mechanically or from contaminates, oil pressure will be high. A plugged oil passage from relief valve to sump or from pump to relief valve may be the problem. Remove relief valve from engine and run a soft copper wire down through oil passage to sump to unclog passage. If blockage persists, remove sump to clear passage

D. Improper relief spring or cold oil.

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Disclaimer: sacskyranch.com contains abundant information relating to aircraft maintenance. The information provided  is not intended to supercede or supplement the F.A.A. approved  maintenance and/or operator’s manuals. Those F.A.A. approved manuals must be utilized when performing maintenance and/or operating aircraft.