Grease Contamination may arise from multiple operating, fluid, sampling or analytical causes. The pattern, rate of change and correlated evidence determine the most credible explanation.
Start with the observation
Confirm sample identity, method, units, service interval and historical baseline. A single abnormal parameter rarely confirms root cause, and a plausible explanation should predict other evidence that can be checked.
Differential diagnosis
| Possible cause | Supporting indicators | Confirming tests | Immediate response | Long-term corrective action |
|---|---|---|---|---|
| Water | Consistency change | elemental analysis icp oes | Collect a representative purge sample | Correct the confirmed source rather than the isolated number |
| Dirt | Discolouration | pq index | Review seals and relubrication practice | Establish a follow-up sampling point and timing |
| Wrong grease mixing | Bearing temperature | analytical ferrography | Collect a representative purge sample | Document maintenance so the post-action trend can be evaluated |
| Process ingress | Consistency change | elemental analysis icp oes | Review seals and relubrication practice | Correct the confirmed source rather than the isolated number |
Confirming and supporting evidence
Confirming tests
Supporting indicators
- Consistency change
- Discolouration
- Bearing temperature
Immediate and corrective actions
| Stage | Objective | Action |
|---|---|---|
| 1 · Verify | Confirm the observation is comparable | Check asset, compartment, sample point, units, method, interval, top-up and maintenance history. |
| 2 · Protect | Control immediate equipment or safety risk | Collect a representative purge sample; Review seals and relubrication practice |
| 3 · Diagnose | Find the source using independent evidence | Use elemental analysis icp oes, pq index, analytical ferrography and relevant inspection evidence. |
| 4 · Correct and confirm | Remove the cause and prove effectiveness | Correct the confirmed source rather than the isolated number; Establish a follow-up sampling point and timing; Document maintenance so the post-action trend can be evaluated |
- 01Collect a representative purge sample
- 02Review seals and relubrication practice
- 03Correct the confirmed source rather than the isolated number
- 04Establish a follow-up sampling point and timing
- 05Document maintenance so the post-action trend can be evaluated
False positives and context checks
- Non-representative sample
- Changed method or laboratory
- Recent top-up or overhaul
- Container or sampling-tool contamination
References and method context
References identify authoritative source families; they do not reproduce protected procedures or acceptance tables. Verify the current official edition before procedural or conformity use.