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Top 5 Common Diesel Engine Issues & Prevention - Part 5

Poor Maintenance

Modern diesel engines are far more advanced and finely tuned than the diesels of the 1980s and 90s. While older diesel engines were famously forgiving, modern ones require more attention and precision, especially in their maintenance routines. With stricter emissions regulations, tighter engineering tolerances, and complex fuel systems, failing to keep up with recommended maintenance can lead to major issues. However, when properly maintained, modern diesel engines can be extremely reliable and perform at a very high level.

A) Oils Ain’t Oils

Using the correct oil for your diesel engine is critical, especially with the complexity of modern diesel emissions systems.

  1. Emissions Systems Compatibility:
    Diesel engines equipped with Diesel Particulate Filters (DPFs) require very specific low-ash oils. When the oil vapor from the crankcase breather is drawn into the intake and eventually burned off in the combustion chamber, it must burn completely without leaving ash residues. If the oil doesn’t meet these stringent requirements, ash will build up in the DPF. Unlike soot, ash cannot be burned off during regeneration, and over time it will clog the DPF. This will eventually require the DPF to be removed for cleaning or replacement, a costly and avoidable procedure
  2. Manufacturing Tolerances:
    Modern diesel engines are engineered to incredibly tight tolerances. Fuel system components operate at pressures exceeding 2,000 bar, and many engine parts are measured and manufactured down to the micron level (one-thousandth of a millimeter). For example, the Nissan V9X engine has more than 30 different bearing shell options to ensure a perfect fit based on measurements of the block and crank. This level of precision means that the “she’ll be right” mentality of older engines no longer applies—using the wrong oil or skimping on maintenance can lead to catastrophic engine damage.

B) More Data – Blessing or Curse?

The wealth of data that modern diesel engines provide is a double-edged sword. On one hand, it allows for incredibly detailed diagnostics; on the other hand, it requires a highly skilled mechanic to interpret the data properly.

  1. Understanding the Data:
    Modern diesel engines can output hundreds of live data points, from injector performance to intake manifold pressure. A skilled mechanic can use this data to assess the health of the engine, diagnose issues before they become critical, and fine-tune the performance. This proactive approach can help spot failing injectors or a clogged intake manifold early, preventing more serious (and expensive) problems down the road​
  2. The Importance of a Good Mechanic:
    Whether you love or loathe your diesel engine may come down to the mechanic who services it. An experienced mechanic who understands how to interpret engine data can provide early warnings on potential issues. For instance, they can assess how your injectors are performing or estimate the blockage level in your intake manifold, offering preventive maintenance suggestions. This allows you to fix small issues before they snowball into bigger, more costly ones

Conclusion

Proper maintenance is the key to unlocking the full potential and reliability of a modern diesel engine. While these engines are marvels of engineering, they are also less forgiving than their predecessors. Failing to use the right oil or skipping timely maintenance can lead to clogged DPFs, excessive soot production, and even severe engine damage. By ensuring regular servicing with the correct products and relying on a knowledgeable mechanic, you can avoid these pitfalls and enjoy the powerful, efficient performance that modern diesels offer.

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