Mercury MerCruiser D2.8L D-Tronic Service Manual page 655

SERVICE MANUAL NUMBER 22
Troubleshooting Charts (Continued)
CONDITION
COOLANT
TEMPERATURE
ABOVE
NORMAL
90-860074--1 FEBRUARY 2002
POSSIBLE CAUSES
1. Low coolant level.
2. Incorrect/improperly
operating pressure cap.
3. Loose drive belt on water
pump.
4. Improperly operating
temperature sensor / gauge
5. Obstructed or restricted
seawater pump inlet.
6. Improperly operating.
incorrect or no thermostat.
7. Air in the cooling system.
8. Inoperative water pump.
9. Incorrect injection pump
timing.
10. Over fueled injection pump.
11. Plugged cooling passages in
coolers/heat exchanger,
head, head gasket or block.
12. Engine overloaded.
EDI DIAGNOSIS
CORRECTION
1. Check coolant level. Add
coolant, if necessary. Locate
and correct the source Off
the coolant loss, (refer to
Group, Cooling).
2. Replace cap with the correct
rating for the system.
3. Check/replace belt or belt
tensioner.
4. Verify that the gauge and
temperature sensor are
accurate. Replace
gauge/sensor, if bad.
5. Remove obstruction /
restriction.
6. Check and replace the
thermostat.
7. (A) Make sure the fill rate is
not being exceeded and the
correct vented thermostat is
installed.
(B) Check for loose hose
Camps. Tighten if loose. (C)
If aeration continued, check
for a compression leak
through the head gasket.
8. Check and replace the water
pump.
9. Verify pump timing marks are
aligned. Check/time the
injector pump (refer to
Group, Fuel System).
10. Repair or replace the
injection pump.
11. Flush the system and fill with
clean coolant.
12. Verify that the engine load
rating is not being exceeded.
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