Top off the fuel tank if possible
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 and fully charge batteries and 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 extreme cold weather. Find a time when temperature is above freezing to start the machine, and fully warm hydraulics after the engine comes to operating temperature.
Do not try to break crawler type machines from a badly frozen situation.
The result can be powertrain damage.