Medium Duty Operator's Manual - Peterbilt Motors Company

Preventive Maintenance
What To Check In An ELC-filled Cooling System
ELC Concentration
Check the level of freeze/boilover protection, which is
determined by the ELC concentration. Use a glycol refractometer
to determine glycol level. Add ELC to obtain the
ELC to water ratio required to provide the protection you
need. Use the chart below to help determine how much
ELC you need to add.
Engine Cooling System
NOTE: Maximum recommended ELC concentration
is 60% ELC and 40% water by volume (a 60/
40 coolant mixture). The minimum recommended
concentration is 40%.
In an ELC-filled cooling system, the freeze point should be
maintained between -30° F and -45° F (-34° C and -43° C)
Desired ELC/
Water ratio:
0% 10% 15% 20% 25% 30% 35% 40% 45% 50% 55% 60% 65% 70% 75% 80% 85% 90% 100%
Freeze point
°F (°C)
+32
(0)
+25
(-4)
+20
(-7)
+15
(-9)
+10
(-12)
+5
(-15)
-5
(-21)
-12
(-24)
-23
(-31)
-34
(-37)
-50
(-46)
-65
(-54)
-75
(-59)
-84
(-64)
-70
(-57)
-55
(-48)
-43
(-42)
-30
(-34)
-5
(-21)
ELC Condition (Contamination and Inhibitor Concentration)
Perform a visual inspection of the ELC. It should have no
cloudiness or floating debris. Determine the chemical
inhibitor concentration level by using an ELC-specific test
kit or test strips. Inhibitor concentration level determines
corrosion protection. If you are concerned about possible
coolant quality, contamination, or mechanical problems,
submit a coolant sample for analysis. Improper maintenance
may cause coolant degradation and could result in
damage to the cooling system and engine components.
Consult your dealer or the ELC manufacturer’s representative
for recommended ELC test kits, test strips, and laboratory
sample procedures.
ELC Extender
Add ELC extender if necessary at the maintenance interval
under “Cooling” on page 179.
Medium Duty (R05/09) Y53-6008A – 175 –