Description
Before starting engine each day, check to ensure that
coolant is visible in coolant recovery bottle.
There are several configurations of this cooling sys-
tem, but the operation is essentially identical. Basi-
cally, the system is composed of two separate sub-
systems: the seawater system and the closed
cooling system. The seawater system is similar in
function to the fan used in an automobile because it
absorbs heat (from the closed cooling system) as it
passes through the heat exchanger. The closed cool-
ing system is similar in function to the rest of the cool-
ing system in an automobile.
If coolant is not visible, check fresh water section of
cooling system (including coolant recovery system)
for leaks and repair, as necessary. Refill fresh water
section with recommended coolant solution, as out-
lined under “Changing Coolant,” following.
If coolant is visible, start engine and run until it reach-
es normal operating temperature, then recheck cool-
ant level in coolant recovery bottle. Coolant level
MUST BE between the ADD and FULL marks (on
front of bottle).
The coolant recovery system keeps the reservoir full.
Normal coolant overflow into recovery bottle is ap-
proximately 1/2 pint (230 mL) during warm-up. The
coolant recovery system draws coolant back into the
reservoir from the recovery bottle as the engine
cools. As long as there is coolant in the recovery
bottle, the reservoir should remain completely full. If
not, there’s a vacuum leak, usually at the hose leav-
ing the reservoir, or the gasket under the recovery fill-
er cap. The gasket seals against the outer rim of the
filler neck.
! WARNING
Allow engine to cool before removing pressure
cap, as sudden loss of pressure could cause hot
coolant to boil and discharge violently. After en-
gine has cooled, turn cap 1/4 turn to allow any
pressure to escape slowly, then push down and
turn cap all the way off.
If level is low, remove fill cap from coolant recovery
bottle and add required amount of coolant solution.
Use a 50/50 mixture of ethylene glycol antifreeze and
pure,softwaterforcoolantadditions.Iffrequentaddi-
tions of coolant are required, check fresh water sec-
tion for leaks.
IMPORTANT: The coolant (antifreeze) flows
around the outside of the cooling tubes while
seawater flows through the inside of the cooling
tubes in the heat exchanger.
IMPORTANT: ALCOHOL OR METHANOL BASE
ANTIFREEZE OR PLAIN WATER ARE NOT REC-
OMMENDED FOR USE IN COOLING SYSTEM AT
ANY TIME. In areas where ethylene glycol is not
available, and the possibility of freezing does not
exist, it is permissible to use a solution of rust in-
hibitor and pure, soft water (mixed to manufac-
turer’s recommendations).
Maintaining Coolant Level
a
Occasionally, check to ensure that coolant recovery
system is functioning properly by removing pressure
capfromheatexchangerandcheckinglevel.Coolant
level should be up to bottom of heat exchanger filler
neck. If low, examine entire fresh water section (es-
pecially coolant recovery system) for leaks and re-
pair, if necessary.
72520
IMPORTANT: When reinstalling pressure cap, be
sure to tighten it until it contacts stops on filler
neck.
Coolant Recovery Bottle
a - Fill Cap
Index
6B-2 - CLOSED COOLING SYSTEMS
90-823224--2 796
| Categories | Mercury MerCruiser Manuals |
|---|---|
| Tags | Mercury MerCruiser 454 CID, Mercury MerCruiser 502 CID |
| Model Year | 1993, 1994, 1995, 1996, 1997 |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
(4 votes, average: 4.5 out of 5)
Marine readers have rated 1993 1997 Mercury-MerCruiser GM V8 454 CID 7.4L and 502 CID 8.2L Marine Engines Service Manual Number 16 4.5 out of 5.0 based on 4 product reviews. Hugely helpful service manual! Perfect. Thank you!
Manuals are all Important for Technician
This book is invaluable if you do your own repairs. Great book.
Could not find a copy until a search brought me here.
Excellent print.
Thank you