Bearings fail on a seasonal cycle. Cold-start failures cluster in the first hard frosts of autumn; lubrication breakdown and thermal expansion issues spike in the summer heat; contamination surges during spring wash-downs and autumn wet weather. Treating bearing inspection as a quarterly, season-specific routine — rather than a single annual check — catches the failure modes that actually kill your machinery.
This guide gives engineers a practical, season-by-season inspection routine that aligns with how bearings actually behave across the year. It is the first in our Bearing Maintenance series.
Why Seasonal Inspection Matters
A bearing that runs perfectly in May can fail in November for reasons that have nothing to do with load and everything to do with temperature, viscosity and condensation. The four seasonal shifts each create a distinct failure signature:
- Winter: grease stiffens, cold-start shock loads cages and raceways, condensation corrodes
- Spring: wash-downs and humidity drive water ingress past seals
- Summer: heat thins lubricant, thermal growth changes clearance, overheating peaks
- Autumn: falling temperatures reverse summer expansion, wet weather returns, debris from outdoor work contaminates housings
A single annual inspection misses all four windows. Quarterly, season-tuned inspection catches each failure mode at the right time.
Winter Inspection (December–February)
1. Cold-Start Lubrication Check Cold grease does not flow. Before the first cold snap, verify that the lubricant in service is rated for your lowest expected starting temperature. Standard lithium EP greases stiffen below 0°C, starving the bearing of film at the exact moment cold-start shock load is highest.
Action: Confirm grease operating temperature range. For outdoor or cold-store applications, switch to a synthetic low-temperature grease (rated to -30°C or below) before the first frost.
2. Condensation and Corrosion Cold bearings cycling between cold soak and operating temperature draw condensation into the housing. Water displaces the lubricant film and pitting corrosion begins within days.
Action: Inspect housings for water traces, check drain plugs, and verify seal integrity. Re-grease to purge any water that has already ingressed.
3. Clearance and Preload Under Cold Shock Cold-start shock load can crack raceways that survived all summer. Listen for new startup noise and check for axial play that indicates cage or race damage.
Action: Bar-over each critical bearing cold, then run to temperature, and note any change in vibration or noise signature.
Spring Inspection (March–May)
1. Post-Winter Wash-Down Inspection Spring cleaning and wash-down routines drive water past seals that survived winter but are now aged. Check every washed-down bearing for water ingress and grease wash-out.
Action: Open a sample of housings, inspect grease condition (cloudy or milky grease = water contamination), and replace seals showing hardening or wear.
2. Seal and Shield Audit Winter cold hardens nitrile seals; spring is when that damage shows up as leaks. Audit seal lip condition and shield integrity across the plant.
Action: Replace any seal with a hardened, cracked or flattened lip. Consider upgrading to Viton or labyrinth seals in wash-down zones.
3. Re-Greasing After Winter Purge If you purged water-contaminated grease through winter, spring is the time to re-establish the correct fill and relubrication interval.
Action: Set the correct grease fill (typically 30–50% of the free internal space for high-speed, more for slow), and reset the auto-luber interval.
Summer Inspection (June–August)
1. Operating Temperature Audit Summer is when marginal lubrication becomes failure. Walk the plant with a non-contact thermometer and log running temperatures. Any bearing running more than 10°C above its baseline is a candidate for failure.
Action: Flag bearings above 70°C (or above the grease rating). Check lubrication first, then alignment and load, before considering a high-temperature grease upgrade.
2. Thermal Expansion and Clearance Heat expands shafts and housings. A bearing that was correctly clearance-fitted in spring may be running tight by mid-summer, raising temperature further.
Action: Verify running clearance is still within spec. For high-heat applications, confirm you are using the correct internal clearance class (C3 or C4) to absorb thermal growth.
3. Lubricant Film Strength Thin, hot oil film lets metal touch metal. Confirm the lubricant viscosity is still adequate at summer operating temperature.
Action: Cross-check your grease's viscosity at operating temperature. If film strength is marginal, move to a higher-viscosity or synthetic high-temperature grease.
Autumn Inspection (September–November)
1. Reverse Thermal Growth Check As temperatures fall, the summer expansion that loosened fits reverses. Bearings that ran hot and loose in August can suddenly run tight and noisy in October as housings contract.
Action: Re-check running clearance and noise as temperatures drop. Re-confirm fits and preload settings before the cold season.
2. Wet-Weather Contamination Autumn wet weather and outdoor plant work drive debris and water into bearings. Inspect for ingress, especially on conveyors, outdoor drives and plant entrances.
Action: Clean and re-grease, replace any damaged seals, and fit covers or shields where debris is recurring.
3. Pre-Winter Lubricant Switch If you run a summer-grade grease, autumn is the window to switch back to a cold-rated lubricant before the first frost — not after the first cold-start failure.
Action: Schedule the winter grease change in October, not December. Purge the old grease fully to avoid mixing incompatible lubricants.
The Engineer's Seasonal Checklist
Use this four-point checklist at every seasonal inspection to keep the routine consistent across the team.
- Log running temperature and compare to last season's baseline
- Inspect grease condition and water contamination
- Check seal and shield integrity
- Verify running clearance, preload and fit for the new temperature range
Quick Reference: Seasonal Failure Modes
| Season | Primary failure mode | Inspection focus |
|---|---|---|
| Winter | Cold-start shock, condensation | Grease cold-flow, water ingress, startup noise |
| Spring | Wash-down water ingress | Seal condition, grease wash-out, water contamination |
| Summer | Overheating, thin film | Running temperature, clearance, lubricant viscosity |
| Autumn | Reverse growth, wet contamination | Clearance re-check, ingress, pre-winter grease switch |
When to Call in Support
Seasonal inspection catches the common modes, but some bearings need more than a walk-around. If you find a bearing running hot, noisy or loose that does not respond to relubrication and clearance correction, stop it before it fails and ask for a vibration and condition-monitoring assessment.
Howcroft Group's technical team supports engineers across our 30-mile service area with same-day bearing supply, condition-monitoring support and a 24hr emergency breakdown line on 01709 878282. We stock 17,000+ bearing lines including ISB, SKF and FAG for rapid collection from our Rotherham depot.
This is the first guide in our Bearing Maintenance series. The next covers lubrication intervals and the 80/20 rule for relubrication frequency.
