AUTONEWS

The Mini Part That's Killing Many Diesel Engines, Rapidly Reducing Their Lifespan

Many diesel engines are dramatically shortening their lifespans due to a series of failures that, this time, go beyond the much-discussed timing belts. These weak points are located in the exhaust gas recirculation systems.

Many diesel engines are dying too early. The reasons are fairly well known by now, and the weak point can be found, aside from the aforementioned and occasional failures in certain timing belts of many manufacturers, this time primarily in the exhaust gas recirculation systems. Today, thanks to a report prepared by our German colleagues at Auto Motor und Sport, we're going to try to explain how to detect and prevent these potentially costly mechanical damages early on.

Countless diesel engines consume too much oil and, therefore, reduce their lifespan. At Volkswagen, for example, some generations of the T5 and T6 vans, very popular in Europe and extremely spacious and always reliable, have suffered from the problem. But many manufacturers encounter the same defect seen in engines with very low mileage. Why?

The good news is that the damage is predictable, as the reasons have long been known, and owners can take countermeasures in advance. The bad news is that manufacturers rarely cover all the costs, even though the car is clearly not under warranty, even if it is clearly a factory design defect.

The message of fear: "Engine failure"..."Engine failure." It's a very broad and common word, one that can start everything and can be caused by many causes. In most cases, it is actually caused by mechanical damage to the piston and/or valve train, caused by inadequate lubrication. This breakdown of the oil film often occurs because the engine overheats and the oil becomes too liquid.

The causes of damage in diesel engines are often found in exhaust gas recirculation and aftertreatment. Some engines suffer from severe soot buildup or a clogged EGR system. This exhaust gas recirculation system redirects part of the exhaust gas directly to the intake tract through a bypass to lower combustion temperatures (less oxygen) and reduce NOx emissions. If the valve sticks and remains open, for example, too much hot exhaust gas enters the combustion chamber. The consequences are the aforementioned thermal damage to the cylinder head or piston rings.

Clogged diesel particulate filter (DPF)...During normal operation, the diesel particulate filter is designed to capture soot particles and burn them regularly in a concentrated regeneration cycle. However, for the necessary cycle to occur, the engine and exhaust system must first be properly warmed up. If there are too many short trips on the logbook, regeneration cycles may be missing or incorrect. Then, over time, the filter clogs, and the engine experiences excessive exhaust back pressure.

In this case, too, overheating and damage to the piston drive can occur. However, the turbocharger will be damaged sooner. If DPF regeneration fails, diesel can also enter the engine oil. This accelerates the oil dilution effect and can even lead to damage to the crankshaft and connecting rod bearings. Incidentally, faulty regenerations can also be caused by incorrect software.

How can I avoid this engine damage?...First of all, it's helpful to strictly adhere to the oil change interval. Experts even recommend shortening it to 15,000 kilometers. Furthermore, the vehicle itself provides information via the fault memory, for example, about the load of the soot particulate filter. Frequent overloading indicates burned oil and, therefore, crankshaft wear. If you want to improve particulate filter regeneration cycles, you can't avoid long trips.

However, too many short trips in everyday life spell doom for any modern diesel engine. If you want to get the most out of your engine, you should consider replacing or upgrading the EGR module. It may also be cost-effective to purchase a larger aftermarket intercooler.

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