Applicable Systems
EC220 Excavator
Symptoms
Hydraulic oil temperature alarm triggers after 30 minutes of digging.
Possible Causes
- Hydraulic oil cooler fins blocked with mud.
- Oil cooler bypass valve stuck closed (or missing spring).
- System working beyond rated duty cycle—continuous relief.
Troubleshooting Steps
- Step 1: Clean cooler fins with pressure washer from fan side outward.
Light passes through entire core area; no blocked passages. - Step 2: Remove bypass valve and check spring free length.
Spring length 45 mm uncompressed; no coil binding. - Step 3: Monitor relief valve activation time via pressure log.
Relief activation < 5% of operating time.
How to Reset
Clean cooler; replace bypass valve if spring damaged; adjust operator technique.
Common Replacement Parts
- Oil Cooler 14562781: Oil Cooler 14562781
- Bypass Valve 11709804: Bypass Valve 11709804
Frequently Asked Questions
- Q: What is normal hydraulic temp for EC220?
60–85°C under load; alarm at 105°C.
Source: Volvo EC220E Hydraulic Manual
Category: Heavy Equipment