Cylinder Oil Drain Analysis & ISM Compliance
Why Cylinder Oil Drain Analysis Matters for Compliance
Cylinder oil drain analysis is an essential part of modern ship maintenance and compliance.
For two-stroke marine diesel engines, it provides early insight into piston and liner condition, verifies proper lubrication, and ensures compliance with the ISM Code, classification society rules, and OEM recommendations.
Monitoring this data is not only good engineering practice—it’s a mandatory requirement under ISM §10 for maintaining machinery in safe operating condition.
What Is Cylinder Oil Drain Analysis?
Cylinder oil drain (or “scrape-down”) analysis involves sampling used cylinder oil from the engine to measure key indicators such as:
This laboratory analysis allows engineers to identify issues like cold corrosion, improper BN selection, or over/under-lubrication before they cause serious damage.
- Base Number (BN) – remaining alkalinity for acid neutralization
- Iron (Fe) – cylinder liner and ring wear
- Viscosity @100 °C – oil degradation or fuel dilution
- Water, insolubles, and metals – contamination and combustion residues
ISM & Class Compliance
1. ISM Code Requirements
ISM Clause Requirement Practical Application
§10 – Maintenance of the Ship and Equipment Ships must be maintained in conformity with rules and regulations. Oil analysis is part of planned maintenance and condition monitoring.
§10.3 – Records of Non-Conformities Maintenance records and reports must be kept. Abnormal analysis results (e.g., high Fe, low BN) require documented corrective action.
§11 – Documentation All maintenance data must be controlled and available for audit. Oil analysis certificates and lab reports are controlled ISM documents.
2. Classification Society Expectations
Typical survey expectations:
Regular oil and drain analysis for main engine and auxiliary systems.
Trending data for BN and Fe content.
Proof of corrective actions where limits are exceeded.
Evidence that oil choice (BN level) matches the fuel sulphur content in line with MARPOL Annex VI.
Example – DNV CG-0172:
“Where condition-based maintenance is applied, results from oil and wear debris analysis shall be presented as part of the survey documentation.”
3. OEM and MARPOL Compliance
For example, MAN Service Letter SL2022-728 specifies:
Regular drain oil sampling for each cylinder.
Monitoring of BN depletion and iron content.
Adjusting oil feed rate or BN grade based on results.
Under MARPOL Annex VI, the correct selection of cylinder oil (BN) must align with the sulphur content of the fuel in use:
0.50 % S (VLSFO) → ~40 BN oil
0.10 % S (ECA fuel) → 15–40 BN oil
High-sulphur HFO (if scrubber fitted) → 100–140 BN oil
Drain oil analysis provides the proof that these requirements are being met in practice.
Next Steps – Get Compliant Today
- Detects liner wear and cold corrosion early.
- Optimizes feed rate and lubricant consumption.
- Prevents costly engine damage.
- Proves ISM §10 compliance and class condition monitoring.
- Demonstrates MARPOL sulphur compliance.
- Enhances fleet efficiency and reliability.
Contact our team to discuss further — we are able to provide the full range of analyses, not only those offered by oil makers and suppliers.