Testing Coolant For Alkalinity; Draining Fresh-Water Cooling System - PCM 2007 5.0L MPI Owner's Operation And Maintenance Manual

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 standard ethylene glycol coolant in the system every
two years to prevent a build-up of harmful chemicals
within the fresh-water system.
WARNING
Do not remove cooling system fi ller cap when
the engine is hot. Allow the engine to cool and
then remove the pressure cap slowly, allowing the
pressure to vent. Hot coolant, under pressure, may
discharge violently and cause severe burns.
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.
Remove DRAIN PLUG
(as equipped)
Figure 11-11 Draining Engine Circulating Pump
(5.0/5.7L)
ENGINE MAINTENANCE - 11
Do not remove cooling system fi ller cap when
the engine is hot. Allow the engine to cool and
then remove the pressure cap slowly, allowing the
pressure to vent. Hot coolant, under pressure, may
discharge violently and cause severe burns.

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
− Remove the large hose from the engine
block water circulating pump, or drain plug as
shown in Figure 11-11.
− Drain plugs on the cylinder block (one on
each side)
2. Remove the following drain plugs to raw water
from the fresh-water cooling system:
− Drain plug on oil cooler
− Drain plug on heat exchanger
− Drain plug on the bottom of each exhaust
manifold
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 tighten
the clamps securely.
L510010-07A
WARNING
37