yearly def pump and def system failure due to cold winters

This DEF reservoir heater kit features a redesigned housing to insure it lasts longer than the factory part and includes all the necessary gaskets,

6.7L DEF Heater/Diesel Exhaust Fluid Reservoir Heater Kit Compatible with 6.7L V8 Ford F250, F350, F450, F550 Super Duty 2011 2012 2013 2014 2015 2016

Tips for Handling DEF in Cold Weather

Managing DEF in cold weather should be a concern

The impact of high temperatures on diesel exhaust fluid

DEF Shelf Life and Storage Powerblanket Temperature Control Solutions

Cold Winter Weather and Your Diesel Fuel - Diesel Direct

What You Need To Know About Diesel Exhaust Fluid (DEF) - Powerblanket

As Heat Pumps Go Mainstream, a Big Question: Can They Handle Real Cold? - The New York Times

How to Fix a Heat Pump Freezing Up in Winter: GREE's Guide for HVAC Contractors

How long does DEF diesel exhaust fluid last?

Cold weather and DEF fluid