Flushing The Closed Cooling System - Mercury MerCruiser D2.8L D-Tronic Service Manual

CLOSED COOLING SYSTEM

Flushing The Closed Cooling System

1. Remove thermostat housing cover.
2. Remove the thermostats and temporarily install housing cover. Torque housing cover
screws to 16 Nm (132 lb-in.).
3. Remove large hex plug from exhaust manifold rear cover. Then, install an adapter to this
opening, suitable for connecting a tap water hose.
NOTE: On engines equipped with auxiliary hot water heater, remove heater hose from fitting
(in place of hex plug).
Hex Plug Drain (Similar With Hot Water Connection)
4. Attach hose from water source to adapter.
5. On engines with Auxiliary Hot Water Heater: Proceed to step 7.
6. On engines without Auxiliary Hot Water Heater: Open cylinder block drain valves.
7. Run tap water through system until discharge water is clean.
NOTE: Catch expelled water in a suitable container and dispose of properly.
8. Shut off water tap.
9. Remove tap water hose and adapter.
10. Install large hex plug, with new sealing washer, on intercooler, or reconnect heater hose.
11. Close cylinder block drain valves if previously opened.
12. Install thermostats in housing.
13. Position a new thermostat housing gasket on housing. Torque housing cover screws to
16 Nm (132 lb-in.).
14. Fill system with required coolant.
Page 6B-20
For instructions on Flushing Seawater Section refer to SECTION 1B - Maintenance.
SERVICE MANUAL NUMBER 22
NOTICE
90-860074--1 FEBRUARY 2002
70192