Usage:
3406B (8TC) PEEC Truck Engines
Reference: Truck Engine News, February 1987, Page 1, "Incorrect Use Of Fuel Heaters Can Reduce Engine Power " on all truck engines.
Only fuel heaters that have thermostats or are self-regulated should be used on 3406B Truck Engines with PEEC (Programmable Electronic Engine Control). As stated in the Reference Article, either the 7C3557 or 7C3558 Heater Kit, both available from Caterpillar, is recommended. Both heaters offer good protection against cold weather fuel problems without the risk of overheating the fuel.
The temperature of the inlet fuel to the transfer pump on PEEC engines must NOT exceed 65 °C (150°F). A higher fuel temperature reduces the life of the electronics and transfer pump check valves, and also reduces horsepower output. Fuel heaters that are not automatically controlled can heat the fuel above 65 °F (150°C).
The PEEC control module is cooled by fuel, but the heat transferred to the fuel is not sufficient to eliminate the need for a heater in cold weather operation. Fuel was selected to cool the unit because there is always flow during engine operation and it has a relatively low temperature. Fuel flows from the tank to the primary filter, through the transfer pump, through cored passages in the electronic control module housing to the secondary filter, and to the injection pumps.