[mustangraven]

most people dont put the cardboard on because their trucks dont run well they do it so they get heat faster int he winter as the radiater does not disipate the heat as quickly when blocked. Diesels just run better whent hey are good and warm and with sub zero temps those big radiators just do too darn good a job. and no I dont use cardboard on my truck my grill cover does the job lol.