Good Maintenance
A high-powered diesel engine is very hard on the coolant. Additive-depleted coolant will not only allow liner cavitation but cause premature failure of the head gaskets, radiator, water pump, freeze plugs, heater core and thermostat. This is especially a concern when purchasing a used diesel truck. Often, the cooling system hasn't been serviced properly.
Since diesel engines have such a large liquid capacity, cooling system test strips are offered to check the level of additives. If the level is low, a bottle of SCA can be mixed in to renew the coolant without a complete change. Checking the additive level should be part of an established maintenance schedule.
When it comes time to buy coolant, make sure it's compatible with a diesel engine, not automotive/light-truck use, which means gasoline powered. If a switch to a product such as the Evans NPG+ is not in your plans, always reference the vehicle owner's manual for the proper coolant, usually identified by its color.
 The refractometer is used...  The refractometer is used to determine the percentage of water still in the engine. A maximum of 5 percent is allowed with the Evans NPG+. |  Reference the owner's manual...  Reference the owner's manual or a shop manual for the proper EG-based coolant. As an example, early Power Stroke engines used conventional green coolant, but the 6.0L required the gold-colored formulation. | |