48-38-01 AERONCA: Applies to Serial Numbers 15AC-1 to 15AC-227 Inclusive, or S15AC-1 to S15AC-227 Inclusive.
Compliance required before operation at temperatures below freezing, but in any case not later than December 1, 1948.
To prevent the possible loss of engine oil pressure and subsequent engine damage during cold weather starting, the present oil cooler installed on the suction side of the engine oil pump must be revised and installed on the pressure side of the pump.
This change involves the following:
1. Installation of an oil cooler adapter assembly, Continental Motors Corp. Drawing 530536 and 530697, replacing pressure oil screen. This pressure oil screen is then used in adapter assembly.
2. Install new suction oil screen, Continental Motors Corp. P/N A20878.
3. Replace present oil cooler bypass spring with a 35 p.s.i. spring.
4. Replumb oil cooler with different fittings and line arrangement.
(Aeronca Service Helps and Hints Bulletin No. 35 covers this same subject.)