Filling The Closed-Cooling System - Mercury MerCruiser Diesel Inboard 2.8L Operation & Maintenance Manual

5. Open the engine block drain plug.
4.2L shown, 2.8L similar
a - Engine block drain plug
6. After the coolant has drained completely, install the intake and exhaust manifold drain plug, the heat exchanger drain plug,
and the engine block drain plug. Tighten all drain plugs securely.
7. If required, clean the closed‑cooling system. See your local Mercury Diesel authorized repair facility.
8.
Fill the system with the specified coolant. Refer to Filling the Closed‑Cooling System.
Filling the Closed‑Cooling System
1. Remove the pressure cap.
a
b
IMPORTANT: Use only the specified coolant.
2. If the coolant is being replaced or the level is low, slowly add the specified coolant to the level indicated in the table.
Coolant level in expansion tank
All models Within 25 mm (1 in.) of the bottom of the filler neck, or between the upper and lower marks, if marked
Description
Mercury Extended Life Antifreeze
Without sufficient cooling water, the engine, the water pump, and other components will overheat and suffer damage. Provide
a sufficient supply of water to the water inlets during operation.
3. Ensure that the seawater pickup pump is supplied cooling water.
4. Do not install the pressure cap. Start and operate the engine at fast idle (1500–1800 RPM). Add coolant if necessary to
maintain the coolant at the level specified previously.
IMPORTANT: When installing the pressure cap, be sure to tighten it securely to avoid coolant loss.
90-8M0133679 JUNE 2017
eng
a -
b -
23302
Where Used
Closed‑cooling system
NOTICE
a
24552
Pressure cap
Coolant expansion tank
Part Number
877770K1
Section 4 - Maintenance
Page 61