Applicable Systems
EMCP 4.2
Symptoms
Engine overheating above 104°C. Coolant loss observed.
Possible Causes
- Coolant thermostat stuck closed preventing radiator flow.
- Radiator externally blocked with debris or mud.
- Cylinder head gasket leaking combustion gases into coolant passage.
Troubleshooting Steps
- Step 1: Check thermostat opening temperature in hot water bath.
Thermostat begins to open at 82–88°C and fully open at 95°C. - Step 2: Inspect radiator fins and clean with low-pressure water or compressed air.
Air flows freely through all core sections; no blocked tubes. - Step 3: Perform combustion leak test on coolant filler neck.
Test fluid remains blue; no combustion gas detected.
How to Reset
Replace thermostat or cylinder head gasket; refill coolant with Cat ELC; purge air from heater circuit.
Common Replacement Parts
- Thermostat 133-3658: Thermostat 133-3658
- Head Gasket Set 437-1385: Head Gasket Set 437-1385
- Cat ELC Coolant 365-8396: Cat ELC Coolant 365-8396
Frequently Asked Questions
- Q: Can I use plain water in an emergency?
Only in emergencies; replace with ELC as soon as possible to prevent corrosion.
- Q: What causes head gasket failure?
Overheating episodes, incorrect torque sequence, or poor coolant maintenance.
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Source: Caterpillar C15 Engine Service Manual
Category: Heavy Equipment
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