Keep the chainsaw cap tight for storage.

Keep the chainsaw gas cap tight for storage — you don’t need to loosen it to let the fuel expand.

The tank and cap are vented for exactly that job. A tight cap still lets pressure equalize through that vent, so a full tank of stabilized fuel expanding in the heat won’t hurt anything. A loose cap, on the other hand, turns the saw into a leak risk: tip it a little, set something on it, or just let it sit long enough, and fuel will find the path of least resistance. Gas evaporates, dirt gets in, and the garage smells like a two-stroke.

So store it full, cap tightened, and maybe crack a window if it’s in a hot shed. The vent will do its thing.

Your saw will be fine — and so will the garage.