Text Box: “THERMOSTAT AND BY-PASS SYSTEM” © ISBN 0-9720927-6-5 TTS Publication No. 110 List price US $15.00 NOTE: This module is extracted from “The Engine Cooling System” and/or “Engine Coolants” The module DOES NOT provide information in addition to that contained in the books. Text Box: TABLE OF CONTENTS Basic operating principles of a passive “wax motor” thermostat and the active, electronically controlled flow control valves now beginning to replace the passive thermostat Inlet and outlet side thermostat system configurations and functional differences By-pass flow rates requirements to produce acceptable localized engine temperatures for all operating conditions Engine water jacket coolant inlet temperature and flow rate requirements required to maintain operating temperatures for all operating conditions and avoid localized hot spots How the thermostat controls the distribution of flows in the radiator, heater and by-pass circuits and the mixing of the flows to produce the required cooling rates and temperature distribution How the thermostat valve position affects flow rates, system resistance, pump pressure head in the radiator, by-pass and heater circuits Thermostat stroke vs. resistance vs. service life