Actually with a Freightliner chassis, you have SANDWICHED cooling system. The CAC (Charge Air Cooler) is in front of the radiator and is where the vast majority of the dirt and debris is deposited.
Yes, you can clean it yourself. Access the top of the motor/fan shroud area-- from bedroom or closet. Use a garden hose/nozzle. If just dirt, that is all you will need. If there is any oil or grease holding the dirt, you will need a cleaner. Dawn, Simple Green Extreme (Aluminum friendly), etc will work.
Be sure to wear old clothes, it is a pain to clean around the fan blades, but the fan blades sling the dirt to the perimeter where it is hard to remove-- particularly the lower perimeter.
Flush until the effluent is clear.
Also make sure your blow by hose has been extended past the radiator to prevent oily mist from getting back into the radiator and intercooler.
This needs to be done once a year.
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