SERVICE MANUAL NUMBER 30
CLOSED COOLING
Testing Closed Cooling System
Testing Coolant for Alkalinity
WARNING
Allow engine to cool before removing pressure cap as 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 remove cap.
Coolant in fresh water section should be changed per Maintenance Schedule recommenda-
tions and should be checked for alkalinity at least once between change intervals.
1.
2.
Obtain pink litmus paper from a local supplier.
Remove pressure cap from coolant reservoir and insert one end of litmus paper into
coolant.
3.
4.
If pink litmus paper turns blue, coolant is alkaline and need not be replaced.
If pink litmus paper remains pink, coolant is not alkaline and MUST BE REPLACED,
refer to Changing Coolant.
Pressure Testing System
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 remove cap.
If coolant section of closed cooling system is suspected of leaking or not holding sufficient
pressure, and no visible signs of leaking can be found, perform the following test:
1.
2.
Remove pressure cap from reservoir.
Clean and inspect pressure cap to ensure that cap is maintaining proper pressure in sys-
tem.
3.
4.
5.
Inspect sealing surfaces for debris or damage that would hinder proper sealing.
Adjust coolant level to full mark on coolant reservoir.
Attach an automotive-type cooling system pressure tester and pressurize closed
cooling section to amount specified in following chart, based on pressure cap rating for
your engine.
Amount of Pressure Applied to Closed
Pressure Cap Rating
Cooling System
15
psi (103 kPa)
19 psi (131 kPa)
6.
Observe gauge reading for approximately two minutes; pressure should not drop during
this time. If pressure drops, proceed with the following steps until leak is found.
INDEX
90-863161
SEPTEMBER 2000
Page 6A-7
| Categories | Mercury MerCruiser Manuals |
|---|---|
| Tags | Mercury MerCruiser 496 CID |
| Model Year | 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
(2 votes, average: 4 out of 4)
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Great down load . it was all there an more