Narrative:

I wish to bring to your attention a matter of aviation safety. In early may experienced a sudden drop of oil pressure and grounded a cessna 175C aircraft with a GO300E engine. Not being able to solve the problem with external inspection and oil filter change; [I] looked to the [oil] pan; oil filter element and oil relief valve for clues. I did indeed find the problem three days later; the oil relief valve plunger and spring assembly was removed and a small piece of rubber material was mashed to the head of the plunger. Upon additional examination; I discovered more rubber-like material in the oil galley adjacent to the oil relief valve assembly. This resulted in a removal of the engine for access to the accessory case and the oil galley; plus oil pump. Jammed in the oil galley near the oil relief valve plunger seat was an additional piece of rubber gasket material the size of a dime and showing the letters rker. Next day began to comb the engine for any kind of gasket of this sort of and material thickness. A web search turned up a gasket manufacturer named parker. Reading this and seeing what type gaskets parker supplied; I went back to my past oil filters used with an air data computer remote spin-on oil filter stc #SA00402SE to this engine. I had four. Two only had the paper elements remaining with debris for examination and two most recent; 100 or so hours; where I retained the filter-can; plus gaskets and elements. Here I did indeed find two gaskets with parker imprinted on them. One was intact and the second had a split in it. Both were also numbered as parker aa-30850. This was a match to the dime sized piece of rubber gasket found in the oil relief valve with 'rker' lettering. Conclusion: the gasket in the tempest aa-48108 oil filter (C-3210) broke-off some time in the past and allowed a piece; or pieces; of rubber material to go through the engine. Since I do not know how much of the gasket went to the engine; a further search and flushing is in order.

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Original NASA ASRS Text

Title: A Technician reports a Cessna 175C with a GO300E engine experienced a sudden drop of oil pressure. Pieces of rubber like gasket material were found mashed in the oil relief valve plunger head and oil galley area. A clapper valve type filter gasket and crossed oil lines are suspected. Three oil filter manufacturers supply two types of filters for the FAA/STC approved remote spin-on oil filter adapter.

Narrative: I wish to bring to your attention a matter of aviation safety. In early May experienced a sudden drop of oil pressure and grounded a Cessna 175C aircraft with a GO300E engine. Not being able to solve the problem with external inspection and oil filter change; [I] looked to the [oil] pan; oil filter element and oil relief valve for clues. I did indeed find the problem three days later; the Oil Relief Valve Plunger and spring assembly was removed and a small piece of rubber material was mashed to the head of the plunger. Upon additional examination; I discovered more rubber-like material in the oil galley adjacent to the oil relief valve assembly. This resulted in a removal of the engine for access to the accessory case and the oil galley; plus oil pump. Jammed in the oil galley near the Oil Relief Valve Plunger seat was an additional piece of rubber gasket material the size of a dime and showing the letters RKER. Next day began to comb the engine for any kind of gasket of this sort of and material thickness. A web search turned up a gasket manufacturer named PARKER. Reading this and seeing what type gaskets PARKER supplied; I went back to my past oil filters used with an ADC remote spin-on oil filter STC #SA00402SE to this engine. I had four. Two only had the paper elements remaining with debris for examination and two most recent; 100 or so hours; where I retained the filter-can; plus gaskets and elements. Here I did indeed find two gaskets with PARKER imprinted on them. One was intact and the second had a split in it. Both were also numbered as PARKER AA-30850. This was a match to the dime sized piece of rubber gasket found in the Oil Relief Valve with 'RKER' lettering. Conclusion: The gasket in the Tempest AA-48108 oil filter (C-3210) broke-off some time in the past and allowed a piece; or pieces; of rubber material to go through the engine. Since I do not know how much of the gasket went to the engine; a further search and flushing is in order.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.