BOLT 1837121 - Caterpillar

3406B Truck Engines (7FB35917-Up) Equipped With Air-To-Air Aftercoolers (ATAAC)The following information was printed earlier in the September 1985 issue of Truck Engine News on Page 3 as part of the article "New Air-To-Air Aftercooler Ar rangement Used On Truck Engines ".
Caterpillar discourages the use of winter fronts and shutters on air-to-air aftercooled engines. If a winter front must be used, a minimum of 20% of core surface must remain open to air flow under all operating conditions.
To maintain an adequate water pump cavitation temperature for efficient pump performance in an air-to-air aftercooled engine, Caterpillar recommends that the cool ant mixture contain a minimum of 30% ethylene glycol, but no more than needed for the desired temperatureprotection. Dowtherm 209 Full-Fill Coolant cannot be substituted for ethylene glycol due to its inability to raise the water pump cavitation temperature.