"Could the pressure release valve be the culprit?" Looks pretty much like it. Interesting that you can repeat the behavior.
Taking out that valve and checking for wear is easy. I'd do that first . Hartmut ----- Original Message ----- From: Daniel To: [email protected] Sent: Saturday, May 17, 2008 6:18 AM Subject: [ercoupe-tech] Low oil pressure I usually fly my 75HP 415C twice the same day. Two weeks ago everything was fine during the first flight with oil pressure readings over 30psi at cruise and 10psi at idle but during the second flight oil pressure dropped up to 20psi at cruise/10psi at idle. Last Saturday I experienced the same: first flight 45 min with normal pressure readings, let rest the plane 30 min, second flight 20 psi at cruise, 10 psi at idle. Oil temp was always 170F. Could the pressure release valve be the culprit? Daniel
