We keep our Cessna 172 engine compartment/oil sump toasty warm with a 75
watt light bult and an arctic insulated nose cover. The oil drips off
the dipstick even below 0F. A small ceramic heater in the cabin during
pre-flight warms up the gyros and (very importantly) the windscreen, to
keep it from fogging up during our taxi to the runway. When I started
it at +2F a couple of weeks ago, I did need to use a couple extra shots
of prime to get enough gas to atomize. Oil pressure came up quickly.

The down side: during my descent into out destination, the cabin heat
diminished substantially. Brrrrr.

Al
1964 Skyhawk
SFF-Spokane, WA