SERVICE MANUAL NUMBER 24
CLOSED COOLED MODELS
Changing Coolant
NOTICE
For information and procedures on draining the seawater cooling system of
Seawater Cooled (Raw–water) Models, refer to SECTION 6A. For information and
procedures on draining the Seawater Section of Closed Cooling (Coolant) Models
refer to SECTION 1B. For cold weather or extended storage, refer to SECTION 1B.
Closed Cooling Section
Closed cooling section of closed cooling system should be kept filled year-round with
recommended coolant solution. Do not drain closed cooling section for storage, as this will
promote rusting of internal surfaces. If engine will be exposed to freezing temperatures,
make sure that closed cooling section is filled with Extended Life Coolant or an ethylene
glycol antifreeze and water solution, mixed to manufacturer’s recommended proportions,
to protect engine to lowest temperature to which it will be exposed. If necessary, change
coolant using coolant specified in “Coolant Recommendations.”
Change Intervals
If the closed cooling system is factory installed, drain and flush coolant from the closed cool-
ing system at least every five years or 1000 hours of operation, whichever comes first. It
should also be changed whenever exhaust gases have entered the system.
If the system is not factory installed or has had anti-freeze other than Extended Life Coolant
added, it must be changed every two years or 400 hours of operation, whichever comes first.
Draining Instructions
WARNING
Allow engine to cool before removing pressure cap. Sudden loss of pressure could
cause hot coolant to boil and discharge violently. After engine has cooled, turn cap
1/4
turn to allow any pressure to escape slowly, then push down and turn cap all the
way off.
IMPORTANT: A wire should be inserted into drain holes to ensure that foreign
material is not obstructing the drain holes. On some models with two piece petcock,
removal of petcock may be required so that wire can be inserted completely into drain
hole.
IMPORTANT: Engine must be as level as possible to ensure complete draining of
cooling system.
IMPORTANT: Closed cooling section must be kept filled year round with recom-
mended coolant. If engine will be exposed to freezing temperatures, make sure
closed cooling section is filled with Extended Life Coolant or an ethylene glycol anti-
freeze and water solution properly mixed to protect engine to lowest temperature to
which it will be exposed.
The following draining instructions apply to all engines equipped with closed cooling. The
location of petcocks that require opening and hoses that require removal are represented
on the following pages for the individual engines.
IMPORTANT: Observe precautions previously outlined before proceeding.
1.
2.
Remove pressure cap from coolant tank.
Drain coolant from locations as shown in the “Draining Diagram.”
Index
90-861327--1
OCTOBER 1999
Page 6B-13
| Categories | Mercury MerCruiser Manuals |
|---|---|
| Tags | Mercury MerCruiser 305 CID, Mercury MerCruiser 350 CID |
| Model Year | 1998, 1999, 2000, 2001 |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
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