Cooling System

Overview of the normally-aspirated 944 cooling system flow path, including thermostat operation at 83 °C and vacuum-controlled heater core flow.

Overview of the turbocharged 944 cooling system, including thermostat operation, turbocharger cooling circuit with electric post-shutdown pump, turbo thermostat, and check valve.

Step-by-step procedures for draining the 944 cooling system at the radiator and block drain plug, filling with the correct antifreeze mixture, and pressure-venting air from the system.

Explains how the electric cooling fans work on pre-1985.5 and 1985.5+ 944s, with troubleshooting tables and relay/thermofan switch testing procedures for each configuration.

Complete procedure for removing and installing the radiator on normally-aspirated and turbocharged 944s, including fan assembly and coolant hose disconnection.

Procedure for replacing the thermofan switch on the 944, including coolant drain, fan assembly removal, torque specs for plastic and brass thread bosses.

Explains the two thermostat types for the 924S/944/944 Turbo (determined by water pump style), provides all part numbers, and gives complete replacement and bench-testing procedures.

Diagnostic guide covering overheating, temperature fluctuation, fans running after shutdown, and coolant loss on the 944.

Covers the two styles of 944/924S water pump, all part numbers including guard rail, thermostat, and turbo nozzle components, and the complete replacement procedure requiring timing belt removal.