CONSTRUCTION MACHINERY · VERIFIED COVERAGE
Excavator Technical Dossier: Engine, Hydraulics, Diagnostics and Measurement
A construction-machinery class dossier connecting verified OEM applications with engine, electro-hydraulic architecture, symptom discrimination and measurement strategy.
Verified model families
Instead of publishing hundreds of catalogue names, this list exposes existing model pages only after they pass the OEM-primary evidence gate.
OEM-evidenced applicationCaterpillar 320
Caterpillar lists a Cat C7.1 engine application on the current 320 product page.
→OEM-evidenced applicationCaterpillar 330Caterpillar lists the Cat C7.1 as the engine model on the current 330 product page.
→OEM-evidenced applicationKomatsu PC210Komatsu Australia lists 123 kW (165 hp) net power for the PC210LC-11.
→Excavator system architecture
- Engine/ECM load and derate state limit the mechanical power actually available to the hydraulic pump, so an “all functions slow” complaint does not automatically condemn the pump.
- Electronic control/pump demand, hydraulic pump, main control valve, then boom, stick, bucket, travel and swing circuits are separate diagnostic layers.
- A single weak function must be separated into spool/valve, actuator internal leakage, local sensor/command or mechanical load before blaming global pump capacity.
- Aftertreatment or engine-protection derate can feel like hydraulic performance loss; capture active DTC/derate state and engine speed before hydraulic testing.
Symptom → test branch
| All implement/travel functions slow | Engine RPM + derate/fault → pump demand → shared hydraulic pressure/flow. Do not start by replacing a local cylinder. |
|---|---|
| One boom/stick/bucket function weak | Command/sensor → relevant spool/valve → cylinder drift/internal leakage → mechanical load. Verify the global pump against a comparative function. |
| Swing slow / will not hold | Swing command → hydraulic supply → swing motor → planetary reduction / holding brake. Implement pressure alone does not clear the swing mechanism. |
| Slows when hot | Oil temperature + cooling → viscosity/leakage → prolonged relief → pump/valve internal leakage. Compare cold and hot measurements at the same load. |
| DTC/derate with power loss | Resolve the engine/emissions protection cause first; a hydraulic-capacity test performed at reduced engine power can mislead diagnosis. |
Measurement sequence
- Record machine product identity/serial number, attachment and actual operating condition; do not mix service values between different configurations in the same model family.
- Before clearing codes, capture active/history DTCs, derate state, engine speed, load and supported electronic pump/valve commands.
- Reproduce the complaint under the same condition and use the correct OEM test port/procedure for pressure/flow so electronic command can be separated from physical response.
- For a single-function complaint, use comparative drift/internal-leakage and valve/actuator testing; when all functions are slow, return to shared supply and engine power.
- After repair, repeat the measurement at the same oil temperature, load and operating mode; code clearing alone is not proof of repair.
Evidence provenance
- Caterpillar 320 Hydraulic Excavator official product data · OEM-primary · 2026-08-15
- Caterpillar 320/320 GC/323 maintenance and service · OEM-primary · 2026-08-15
- Caterpillar 330 Hydraulic Excavator official product data · OEM-primary · 2026-08-15
- 330 Excavator Manuals & Resources - Cat Parts · OEM-primary · 2026-08-15
- Komatsu PC210LC-11 official product page · OEM-primary · 2026-08-15
- Komatsu Komtrax official remote-monitoring reference · OEM-primary · 2026-08-15