Check your co-pilot side heater muff fastener torques - Ours were loose

[scottrsellers]

At our 25hr oil change we noticed missing screw(pic1), so checked screw torques to find all were loose. Couldn’t find a torque figure for #8 sheet metal screws in Lycoming’s torque chart. IA said they should tight enough not to back out(hand tight). Don't overtighten - remember there's lots of thermal expansion/contraction going on here, so I'm calling it just very snug. Added split & flat washers(pic2&3) to all screws which should stop them from backing out/loosening.
When he checked his heater muff screws Mike Pattison found his were loose as well, confirming what we’d been told that this was typical. With heat for winter flying upcoming you should check yours too.