Emissions System Protection

A diesel van fleet operating in low emission zones began experiencing an increase in emissions related warning lights and forced regenerations. Vehicles were compliant on paper, but downtime and driver complaints were increasing.

Initial checks showed no mechanical faults, pointing attention towards servicing practices and engine oil choice.

The operating environment

The fleet operated mainly in urban areas with frequent stop start driving. Engines spent long periods idling and rarely ran at sustained motorway speeds.

This operating pattern placed additional strain on emissions systems, particularly diesel particulate filters.

Reviewing engine oil

The engine oil in use met basic viscosity requirements but was not a low SAPS formulation designed to protect modern emissions systems.

While suitable for older diesel engines, it allowed increased ash build up, contributing to more frequent regeneration cycles.

Changing oil specification

The fleet switched to a low SAPS engine oil that met manufacturer approvals for vehicles fitted with diesel particulate filters.

No other servicing changes were made, allowing the impact of oil choice to be clearly assessed.

The outcome

Regeneration frequency reduced, warning lights became less common, and overall vehicle downtime improved.

Drivers reported smoother operation, and servicing became more predictable under urban driving conditions.

Key takeaway

Modern diesel vehicles rely on correct engine oil to protect emissions systems. Using approved low SAPS oils is essential, particularly for vehicles operating in urban and low emission environments.