TM 9-2320-209-10-1 c. Using the Quilted Engine Compartment Cover. FRAME 1 CAUTION Open aperture flap (1) when engine temperature goes above 180 ºF. If engine temperature keeps going up, take off quilted engine compartment cover (2) completely, so that engine does not overheat. Failure to remove quilted engine compartment cover may cause damage to the engine. 4-385