January 23, 2026
Extended Oil Drain Intervals in Heavy-Duty Fleet Operations
White papers and Technical briefs
Effects of Guardol ECT® on engine cleanliness and wear protection
In heavy-duty fleet operations, fleet managers know that uptime is critical. Engine oil plays a key role in protecting equipment, managing engine wear, and supporting extended oil drain intervals over long haul cycles. This case study examines real-world fleet performance data, including oil analysis and a full engine teardown, to evaluate how extended drain intervals impact engine cleanliness, wear protection, and overall fleet reliability.
Through documented field testing, oil analysis, and teardown inspection after more than 750,000 miles, this lubricant performance study provides insight into how extended drain strategies can:
- reduce fleet downtime
- improve maintenance efficiency
- support long-term engine durability in high-mileage, heavy-duty applications
The extended drain results in this study were achieved using Guardol ECT®.
GUARDOL ECT
SYNTHETIC BLEND
API CK-4 10W-30, 15W-40
Applications
On-highway diesel trucks, off-highway construction, earth moving and mining equipment in severe duty service.
Key Benefits
- Ideal for severe duty service or extended oil drain intervals
- Excellent protection for newer low-emission diesel engines and older diesel engines
- Exclusive Liquid Titanium protection additive provides enhanced oxidation resistance and protection against engine wear

Ready to put Guardol ECT to work? Find a distributor near you.
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