Diesel engines are known for their durability and fuel efficiency, but high emissions can lead to MOT failures, poor engine performance, and environmental concerns. Reducing emissions is not just about passing inspections — it also helps extend engine life and improve fuel economy.
Several factors commonly contribute to elevated diesel emissions:
Substandard fuel – Contaminated or low-quality diesel increases smoke and particulate matter.
Aging or worn components – Fuel injectors, turbochargers, and piston rings that are worn reduce combustion efficiency.
Incorrect or degraded lubricants – High friction and incomplete fuel burning result from poor lubrication.
Airflow and exhaust problems – Blocked air filters, faulty EGR valves, or clogged diesel particulate filters (DPFs) can significantly raise emissions.
Skipped maintenance – Neglecting routine servicing allows minor problems to escalate, affecting both performance and emissions.
Vehicle owners can adopt several strategies to reduce emissions effectively:
Regular engine servicing – Keeps all critical components operating optimally.
Use high-quality diesel lubricants – Minimises friction and promotes cleaner combustion.
Maintain air intake and EGR systems – Ensures proper airflow and combustion efficiency.
Clean DPFs and exhaust systems – Prevents blockages that increase smoke and particulates.
Monitor fuel quality – Avoid low-grade or contaminated diesel.
Eco-friendly additives – Certain lubricants and fuel additives help reduce soot and improve combustion.
Following these steps can help vehicles meet emissions standards, pass the MOT test, and operate more efficiently.
For further guidance on optimising diesel performance and reducing emissions, refer to expert tips for lowering diesel emissions to pass MOT. This resource provides practical advice on fuel, maintenance, and lubrication strategies to keep diesel engines running cleanly and reliably.