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Technical Article
High Exhaust Gas Temperature: Causes and Troubleshooting
High exhaust gas temperature can be caused by poor fuel atomisation, incorrect injection timing, exhaust valve leakage, low compression, turbocharger or scavenge-air problems, overloaded cylinder units, fouled air coolers, or restricted exhaust flow. Diagnosis should compare cylinder-to-cylinder trends rather than one reading alone.
Symptom, possible cause and inspection
| Symptom | Possible cause | Inspection |
|---|---|---|
| One cylinder high | Injector fault, exhaust valve leakage, low compression, or timing issue | Compare indicator diagram, fuel valve, exhaust valve, and compression |
| All cylinders high | Overload, turbocharger/air cooler restriction, fuel quality, or exhaust restriction | Check load, scavenge pressure, air cooler, turbocharger, and exhaust path |
| High after maintenance | Incorrect assembly, timing, or calibration | Review recent work and verify settings against maker procedure |
First checks
- Confirm sensor accuracy and compare trend history
- Compare exhaust temperature, cylinder pressure, scavenge pressure, and load
- Inspect fuel valves and fuel pump/control condition
- Inspect exhaust valve leakage and movement
- Check turbocharger, air cooler, scavenge receiver, and exhaust path
Measurements and acceptance limits
Condition assessment should be based on recorded measurements, visual findings, operating symptoms, and the applicable maker documentation. Acceptable limits should be confirmed against the applicable manufacturer's manual and engine-specific technical documentation.
Need technical assistance?
If inspection, overhaul, troubleshooting, workshop repair, or onboard attendance is required, Dieselmech Group can review the symptoms, engine details, operating history, and available measurements before recommending the next practical step. Contact us at +65 6334 1855, email sales@dieselmech.com.sg, or submit an enquiry through the Contact Us page.
Technical note
This article is for general technical information. Actual procedures, limits, clearances, pressures, temperatures, torque values, and renewal criteria depend on the engine model, configuration, maker revision, service bulletin, vessel procedures, and class requirements. Manufacturer manuals and vessel safety procedures take precedence. Safety-critical work should be carried out by appropriately qualified personnel.
Published by Dieselmech Group Technical Team. For advice on a specific engine or fault, contact our marine engineers.
