Keep the fuel tank full
If you have a diesel engine, leave it completely full during winter months to eliminate the possibility of condensation forming in the fuel tank and spreading. Condensation can clog the fuel filter, which can clog fuel lines, carburetors, and injectors.
Run the engine after cleaning
Run your machine's engine after cleaning the engine and replacing the oil so that a protective film of oil coats the internal parts. The oil coating acts as a rust preventative. Pour a 50/50 mixture of water and antifreeze into the coolant system before running as well to protect the cooling system to -34°F.
Clean & fully charge batteries, then disconnect the power leads
Never store discharged batteries. Colder temperatures slow the discharge rate of fully charged batteries.
Start machines once a month
Avoid starting the machines in extremely cold weather. Find a time when temperature is above freezing to start the machine and operate the hydraulics for a brief time.