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L510001-05
ENGINE MAINTENANCE - 11
TESTING COOLANT FOR ALKALINITY
It is recommended that the coolant in the fresh-water
section be tested each year for alkalinity. Coolant
that is not alkaline has lost the effectiveness of its
rust inhibitors, which can lead to internal corrosion
and cooling system problems. It is recommended to
replace the extended life engine coolant, known as DEX-
COOL™, in the system every fi ve years to prevent
a build-up of harmful chemicals within the fresh-water
system.
1. Obtain red litmus paper from a local supplier
(drugstore, laboratory, etc.).
2. Remove the pressure cap from the coolant fi ller
neck and insert one end of the litmus paper into
the coolant.
3. If red litmus paper turns blue, coolant is alkaline
and does not need to be replaced. If the litmus
paper remains red, the coolant is not alkaline and
must be replaced.
DRAINING FRESH-WATER COOLING SYSTEM
NOTICE: To protect the environment, dispose of
coolant properly. Check your local restrictions for proper
disposal instructions of removed coolant.
NOTICE: Refer to cooling system water fl ow diagrams
for drain locations.
1. Remove the following drain plugs to drain coolant
from the fresh-water cooling system:
− Drain plug on heat exchanger
− The hose and/or drain plugs from the fi tting
on the bottom of the exhaust manifolds (one
on each side)
− Drain plugs from risers
− Drain plugs on the cylinder block (one on
each side)
− Remove the large hose from the engine
block water circulating pump, or drain plug on
circulation pump. (See Figure 11-10.)
2. Remove the following drain plugs to drain raw
water from the fresh-water cooling system:
− Drain plug on oil cooler
− Drain plug on heat exchanger
− Drain plug on fuel cooler canister (returnless
fuel system only)
3. After system has drained completely, coat all
the drain plugs with PerfectSeal (or equivalent)
and reinstall in the proper locations. Reinstall
the hose(s) on the water circulating pump and
the exhaust manifolds and tighten the clamps
securely.
Figure 11-10 Draining Engine Circulating Pump
(5.0/5.7L)
Remove large HOSE, or DRAIN PLUG (if equipped)
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