77-18-01 MOONEY: Amendment 39-3026. Applies to Models M20E (Serial Numbers 101 through 466, 470 through 1217, 1219, 1221, 1223 through 1308, 670001 through 670062, 690001 through 690073, 700001 through 700039, 700041 through 700043, 700045 through 700052, 700055, 700056, 700060, 700061, 21-0001 through 21-1180); M20F (Serial Numbers 670001 through 670363, 670365 through 670385, 670387 through 670482, 670484 through 670539, 680001 through 680206, 690001 through 690090, 690092, 700001 through 700061, 700063, 700066 through 700070, 700072, 22-0001 through 22-1437); M20J (Serial Numbers 24-0001 through 24-0237, 24-0241, 24-0242, 24-0245, 24-0248 through 24-0255) airplanes with a Stewart-Warner model 8432F1 oil cooler. \n\n\tCompliance: Required before further flight, unless already accomplished. \n\n\tTo prevent overheating of engine oil, accomplish the following: \n\n\t1.\tRemove the top cowl on Mooney Model M20J airplanes, the left side cowl on Mooney Model M20E or F airplanes; visually check the engine oil cooler to determine if there is a "V" notch between the center welds and the row of smaller edge notches, as shown in the attached picture, Figure I. \n\n\t\ta.\tIf a "V" notch is found on the fourth (4th) and/or fifth (5th) plate on the side having the oil ports, as displayed in Figure I, and no such "V" notch is found on the opposite side, make an entry in the aircraft maintenance records indicating that this AD has been accomplished, and the airplane may be returned to service. \n\n\t\tb.\tIf no "V" notch is found as depicted in Figure I, or if there are any other similar notches in any other location, replace the oil cooler with an airworthy Stewart-Warner model 8432F1 oil cooler before further flight. \n\n\tA pilot may perform the visual checks outlined in paragraph 1.a. \n\n\tNote: The pilot must make an entry in the maintenance record in accordance with FAR Section 43.9 to indicate compliance with this AD. \n\n\tNote: Mooney Special Notice Letter 7/22/77 pertainsto this same subject. \n\n\t2.\tAny equivalent method of compliance with this AD must be approved by the Chief, Engineering and Manufacturing Branch, Flight Standards Division, Southwest Region, Federal Aviation Administration. \n\n\tThis amendment becomes effective August 31, 1977, and was effective upon receipt of the airmail letter dated August 2, 1977, for all recipients of the airmail letter.