Cooling System - General; Water Quality; Checking Coolant Level; Cooling System Flushing - Northern Lights M844W3 Operator's Manual

COOLING SYSTEM - GENERAL

NOTE: Marine sets – be sure to close the sea-cock
before working on the engine cooling system.
CAUTION: The cooling water in the engine
reaches extremely high temperatures. You must
use extreme caution when working on hot
engines to avoid burns. Allow the engine to cool
before working on the cooling system. Open the
filler cap carefully, using protective clothing
when the engine is warm.

WATER QUALITY

1. Distilled, soft water is preferred for use in cooling
systems. Bottled distilled water from a food store or
water supplier is recommended. Tap water often has
a high mineral content. Tap water should NEVER
be put in a cooling system unless first tested by a
water quality laboratory. Do not use water made by
the reverse osmosis method unless it has been PH
neutralized.
2. Here are acceptable water quality specifications:
Contaminates
Maximum Chlorides
Maximum Sulfates
Maximum Dissolved Solids
Maximum Total Hardness
Updated 11-8-13
Servicing
Parts Grains
per Million per Gallon
40 2.5
100 5.9
340 20.0
170 10.0
PH Level 5.5 to 9.0
OM844W3 5/21
SP-12. CHECK THE COOLANT LEVEL
1. Check the coolant level each day before starting the
engine. Check the water level by removing the
pressure cap from the expansion tank.
In order to give the cooling water an opportunity to
expand, the level should be about 1 in. (2.5 cm) below
the filler cap sealing surface when the engine is cold.
2. The pressure valve in the filler cap releases when the
pressure is approximately 7 PSI (0.5 bar). Use a cap
pressure tester to check cap if you suspect it is faulty.
SP-13. COOLING SYSTEM FLUSHING
1. Flush the cooling system every 2500 hours or every
24 months, whichever comes first.
a. Remove expansion tank cap and drain engine
block.
b. Open block drain cock.
Remove plug in lower left
side of heat exchanger tank.
c. Pour clean water into expansion tank until water
coming from drains is free of discoloration and
sediment. Let water drain completely. Close
drains and refill with recommended mixture.
2. Coolant Specifications:
Use 50% water / 50% ethylene glycol antifreeze mix.
Antifreeze mixture is recommended as a good year-
round coolant, but not methyl alcohol based antifreeze
because of it's effect on non-metallic components
and it's low boiling point. Also, antifreeze with high
silicate should not be used
3. Check hoses and connections and repair any leakage.
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