Service manual

CLOSED COOLED MODELS SERVICE MANUAL NUMBER 26
Page 6B-4 90-861329--1 MARCH 1999
Pressure Cap Maintenance
Pressure cap is designed to maintain pressure in fresh water section of closed cooling
system once the engine has attained normal operating temperature. This raises the boiling
point of the coolant, thereby increasing the efficiency of the cooling system. To help ensure
proper operation, cap should be cleaned, inspected and pressure tested periodically as
follows:
WARNING
Allow engine to cool before removing pressure cap (in next step), 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 push
down and turn cap all the way off.
1. Remove pressure cap from heat exchanger.
2. Wash cap with clean water to remove any deposits or debris from sealing surfaces.
3. Inspect rubber seal on cap for cuts, cracks or other signs of deterioration. If seal is dam-
aged, cap MUST BE replaced.
4. Inspect coolant recovery gasket for deterioration and replace if bad.
5. Check condition of locking tabs on cap. Replace cap if tabs are bent or cracked.
72714
a
b
c
a-Rubber Seal (Cap MUST BE Replaced if Damaged)
b-Gasket (Look for Cracks under Gasket)
c-Locking Tabs (1 Hidden)
6. Refer to “Testing Pressure Cap” and test pressure cap as outlined.
7. Clean sealing surfaces on heat exchanger filler neck with a cloth. Inspect surfaces for
any damage or deposits that may prevent cap from sealing properly.
8. Clean coolant recovery passage in heat exchanger filler neck with a wire and blow out
with compressed air.
72715
a
b
a-Inspect for Damage
b-Clean Coolant Recovery Passages
9. Reinstall pressure cap, being sure to tighten until it contacts stops on filler neck.
Index