Draining Fresh-Water Cooling System - PCM HO303 MPI Owner's Operation And Maintenance Manual

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.
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.
DRAINING FRESH-WATER PORTION OF THE
COOLING SYSTEM
NOTICE: To protect the environment, dispose of
coolant properly. Check your local restrictions for proper
disposal instructions of removed coolant.
NOTICE: In order to drain the raw-water portion of the
systems, refer to WATER FLOW DIAGRAMS section of
this manual for proper locations.
Remove the following drain plugs/hoses in order to drain
the coolant from the fresh-water portion of the cooling
system.
HO303 / EX343 Half-System
A. Fresh-Water drain plug from heat exchanger.
B. Drain plug from coolant pipe as shown in Figure
11-11.
C. Drain plugs from each side of the cylinder block,
these will be the knock sensors.
ENGINE MAINTENANCE - 11
Figure 11-11 Draining Engine Circulating Pump
(5.0/5.7L)
ZR409 / ZR450 Half-System
A. Fresh-Water drain plug from heat exchanger.
B. Remove large hose from the engine block water
circulating pump.
C. Drain plugs from each side of the cylinder block.
ZR409 CES / ZR450 CES Full-System
A. Fresh-Water drain plug from heat exchanger.
B. Remove large hose from the engine block water
circulating pump.
C. Drain plugs from each side of the cylinder block.
D. Remove the hose and/or drain plug from the
bottom of each exhaust manifold.
E. Remove the drain plug from each exhaust
corner.
ZR450 CES Half-System
A. Fresh-Water drain plug from heat exchanger.
B. Remove large hose from the engine block water
circulating pump.
C. Drain plugs from each side of the cylinder block.
NOTE: After the system has drained completely, coat
drain plugs with PerfectSeal (or equivalent) and reinstall
in proper locations. Reinstall hose(s) and tighten clamps
securely as required.
L510010-11
Remove DRAIN PLUG
(as equipped)
35