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• Protecting metals from corroding • Preventing cavitation of the liner
• Preventing coolant from foaming Many additives are depleted during engine operation and these additives need to be
replaced. This can be done through the addition of Supplemental Coolant Additives SCA to Diesel Engine AntifreezeCoolant DEAC or by adding Extender to Extended
Life Coolant ELC.
Additives must be added at the proper concentration. Overconcentration of additives can cause the inhibitors to drop out-of-solution. This can cause a gel compound to
form in the radiator. An overconcentration of additives can produce deposits on water pump seals that can cause water pump seal leakage. A low concentration of additives
can produce the following problems:
1. Pitting 2. Cavitation erosion
3. Rust 4. Scale
5. Foaming
4. Glycol
Glycol in the coolant provides anti-boil protection and freeze protection. Glycol in the coolant prevents water pump cavitation. Glycol in the coolant also reduces cylinder
liner pitting. For optimum performance, Caterpillar recommends a solution that contains a 1:1 mixture of water and of glycol.
Note: Caterpillar engines with air-to-air aftercooling require a minimum of 30 percent glycol in order to prevent water pump cavitation.
Most conventional heavy-duty coolantantifreezes use ethylene glycol. Propylene glycol may also be used. In a mixture that is 50 percent water, ethylene glycol and
propylene glycol have similar properties that are relative to the following elements: heat transfer, freeze protection, control of corrosion and compatibility of the seal.
Check the glycol level of the coolant system with the 1U - 7298 Coolant Tester Group °C or with the 1U-7297 Coolant Tester Group °F. Tables 13 and 14 define the
freeze protection for ethylene glycol and for propylene glycol.
TORQUES FOR BOLTS AND NUTS
The following tables give general torques for metric bolts, nuts, and taperlock studs of Grade 8.8.
The material strength identification is usually shown on the bolt head by numbers 8.8, 10.9, etc.
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When possible, save the original fasteners that are removed from the machine for assembly. If new fasteners are needed, the new fasteners must be the same size as
the fasteners that are being replaced and the same grade as the fasteners that are being replaced.
Note: Metric hardware must be replaced with metric hardware. Check the Parts Manual for the proper replacement part.
Table 10
METRIC ISO THREAD THREAD SIZE
METRIC STANDARD TORQUE
N-m lb ft
M6 12 ± 3
9 ± 2 M8
28 ± 7 20 ± 5
M10 55 ± 10
40 ± 7 M12
100 ± 20 75 ± 15
M14 160 ± 30
120 ± 22 M16
240 ± 40 175 ± 30
M20 460 ± 60
340 ± 45 M24
800 ± 100 600 ± 75
M30 1600 ± 200
1200 ±150 M36
2700 ± 300 2000 ± 225
PERAWATAN PADA UNIT TRUK
1. PM Level 1
