Lubrication programs rarely implode suddenly. They decay slowly through thousands of small, inherited decisions. A substitute oil approved on convenience, a sampling point placed wherever piping allowed, a PM interval written decades ago, and never recalculated. Individually, these don’t cause machine failure. Collectively, they define your long-term failure rates.
These 40 questions expose that slow drift. They reveal whether your lubrication program is truly engineered to control underlying failure mechanisms or simply repeating habits. If a question makes you pause, that pause is diagnostic.
40 Hard Questions
Lubricant Selection & Specification
Do we maintain full lubricant specifications (viscosity grade, base oil, additive chemistry), not just product names?
Are viscosity grades selected using operating temperature range, load, and speed – not copied from OEM sheets or inherited from previous installations?
When did we last verify that actual operating temperatures still justify the viscosity grade we use?
Are lubricants selected with additive systems appropriate for load, temperature severity, water exposure, and confirmed compatible with system metallurgy and seal materials?
Do we enforce a controlled substitution policy to prevent inadvertent chemistry incompatibility or viscosity drift?
Storage & Handling
Are lubricants stored sealed, labeled, and protected from temperature swings that drive oxidation and condensation?
How many times does oil contact ambient air before entering the machine—and can we reduce those exposures?
Are transfer containers dedicated, sealed, color-coded, and never shared among products?
Have we eliminated open funnels, unsealed pails, and top-offs that bypass contamination control?
Are pumps, filter carts, and transfer tools cleaned and inspected under a documented standard?
Contamination Control
Are ISO 4406 cleanliness targets aligned with component sensitivity, OEM guidance, and risk level (e.g., many hydraulics near 16/14/11, critical servo circuits near 14/12/9 or better)?
Do we verify incoming oil cleanliness and filter it when appropriate – balancing filtration aggressiveness with additive retention, especially for polar additives?
Are breathers sized correctly based on reservoir volume, thermal breathing, dynamic level changes, humidity load, and allowable pressure differential, not simply installed because they were available?
Do we replace breathers based on saturation indication or pressure drop, rather than arbitrary time intervals?
Do we distinguish between condensation, direct water ingress, and seal leakage – and trend each using appropriate detection methods (e.g., Karl Fischer, inspections, process controls)?
Grease Application & Management
Are grease intervals determined from bearing dimensions, load, speed, and temperature – not generic schedules?
Are intervals adjusted for contamination load, vibration severity, or extended idle periods?
Do we calculate grease quantity using bearing geometry and correct fill percentages instead of relying on rough guesses?
Are ultrasonic instruments used to guide lubrication by monitoring friction, with established baselines to avoid over-lubrication?
Do we correlate re-lube history with bearing temperature, vibration, and failure events?
Oil Change Intervals
Do we account for temperature – oxidation behavior when setting oil change intervals – recognizing the industry-standard heuristic of ~50% oxidation-rate increase per +10°C above base temperature for mineral oils (with synthetics typically offering better thermal stability)?
Do we use condition-based drain intervals where sampling is robust, and time-based intervals only where access limits or risk justifies them?
Do we trend oxidation, AN/BN, varnish potential, and contamination to safely optimize oil service life?
How many drains last year were triggered by preventable mechanisms such as varnish, sludge, water, or particle load?
Have we quantified the cost of premature drains across all lubricated assets?
Oil Sampling & Analysis
Are sampling points installed to capture representative fluid in the main flow stream, downstream of wear sources, upstream of filters, and away from sumps, drains, and dead legs?
Are samples taken at stable operating temperature and running conditions to establish valid trending baselines?
Are sample bottles clean, sealed, and verified to meet lab-specified cleanliness levels (using bottles compatible with ISO 3722 requirements for hydraulic-fluid contamination testing where applicable) with proper labeling and traceability?
Is the test slate aligned with actual failure modes rather than a generic “full panel” that wastes budget?
Do we trend results, interpret trends, and drive corrective actions – not simply store the reports?
PM Execution & Induced-Failure Prevention
Do PMs explicitly link each lubrication task to the failure mechanism it prevents?
When did we last audit the PM library for poor task design, redundancy, or missing failure modes?
Are PMs structured to avoid induced failures from intrusive work, unnecessary component disturbance, tool contamination, and incompatible grease changes (soap type, base oil, additive chemistry)?
Do technicians follow defined standards for cleanliness, torque, assembly practices, and contamination avoidance?
Are lubrication routes optimized by frequency, asset criticality, and workload, not by tradition or convenience?
Program Governance & Discipline
Is there clear ownership and accountability for lubrication standards, methods, and decision rules?
Are changes to lubricants, sampling practices, intervals, or methods routed through engineering review, not informal discussions?
Do we measure adherence to lubrication standards – not just PM completion?
Are authority limits for deviations clearly defined and consistently respected?
When was the last time we benchmarked our lubrication program externally rather than against our own historical performance?
If these questions uncovered weaknesses, that simply means your lubrication program is showing its age. Programs don’t degrade because people stop trying; they degrade because conditions change, and the standards don’t keep up. The solution isn’t adding more tasks; it’s restoring engineering discipline.
Precision lubrication is built on clarity, not tradition. These 40 questions show exactly where that clarity needs to return.
