Factors in diesel engine failure

The oil in diesel-powered engines is subject to a multitude of adverse factors that substantially deteriorate the oil over time. These factors can include a variety of less-than-ideal operating conditions, as well as mechanically induced issues. The effects of these things often cause unwanted, untimely, and frustratingly high-cost maintenance, repairs, and even complete engine failure.

Oil degradation

Two of the most common causes of significant engine oil deterioration and degradation are fuel dilution and soot. The cumulative detrimental effect of these 2 contaminants on engine reliability and performance, fuel economy, and exhaust stream emissions cannot be understated, because if neglected, the long term maintenance and repair costs can be enormous.

Fuel dilution

Frequent stop and starts of the engine, prolonged idling, short run times, frequent forced Diesel Particulate Filter (DPF) regenerations, city driving, and operating under cold conditions are just a few of the situations that result in fuel dilution of engine oil. Fuel dilution over 2% is considered severe, yet a large percentage of engines suffer from percentages well over 10%!

This degree of dilution is often directly associated with fuel injector problems, Diesel Particulate Filter issues, and less-than-satisfactory fuel combustion efficiency. These potentially disastrous conditions cannot be corrected simply by changing the diluted, contaminated engine oil and expecting the issue to be resolved – the root problem remains and will continue to give ongoing problems leading to eventual engine breakdown and associated overhaul cost, unless pro-active measures are taken early.

The problems…

Fuel dilution in diesel engine oil is usually associated with a number of problems and can include –

  • Increased number of forced DPF regenerations causing large amounts of diesel into the combustion chamber in the hope of burning off carbon and ash deposits on the DPF. A portion of this unburned diesel gets into the oil pan and contaminates the oil.
  • Under very cold operating conditions, the diesel fuel can cause waxing within the engine oil, where paraffin in the diesel crystallizes, causing the oil to thicken significantly. This can be a huge problem, especially during engine start-up as very low oil pressure is produced, with possible oil starvation to critical engine components – crankshaft bearings, hydraulic chain tensioners, etc.
  • Unsaturated aromatic molecules carried in the diesel fuel do not belong in engine oil and can cause all sorts of lubrication deficiencies, particularly the loss of corrosion protection on critical components, as well as excessive thickening of the engine oil, resulting in harmful deposits and oil starvation conditions.
  • Because diesel fuel dilution essentially results in thinner oil, the viscosity of the oil decreases substantially, changing it from a typical 15W40 to around 5W20. As a result, the all-important oil film thickness collapses, resulting in excessive premature wear on all engine components, but most critically, engine bearings, pistons, piston rings, cylinder walls, etc.
  • Faulty fuel injector operation for whatever reason can quickly remove all-important oil residue from cylinder walls and piston rings which speeds up the wear of pistons, rings, and cylinders. This in turn results in engine blow-by and other preventable problems.
  • Concentration levels of inherent additives in the engine oil are significantly reduced through dilution, resulting in the loss of their effectiveness, and subsequent damage to engine components.

Soot contamination

Soot is a direct by-product of the combustion ignition process. And unfortunately, a portion of it will always find its way into the crankcase oil. This is inevitable. The bigger problem occurs when the production level of soot is higher than acceptable limits, and excessive contamination occurs in the engine oil, resulting in oil breakdown and subsequent lack of adequate component lubrication.

When soot concentration levels are abnormal, and/or the makeup of the soot is irregular, serious problems within the engine are created, and without remedial action, will eventually result in unanticipated, unwelcome maintenance and repair costs.

As with fuel dilution contamination, soot contamination of the engine oil cannot be corrected simply by changing the diluted, contaminated engine oil and expecting the issue to be resolved – the root problem remains, and unless pro-active steps are taken early, very costly repairs will be the result.

The problems…

Soot-oil contamination problems –

  • The rate of soot production in a diesel engine is directly related to the combustion efficiency of the engine. Poor fuel quality, low compression pressure, restricted air intake, malfunctioning fuel injectors, etc. all cause high rates of soot production.
  • Modern diesel engines subject to lower emission requirements run incredibly high fuel injection pressure, around 25,000 – 30,000 PSI is the norm. Popular Hydraulic Electronic Unit Injection (HEUI) and similar injection systems, which run oil pressures between 500 – 3500 PSI in the high-pressure circuit, are especially prone to costly wear caused by abrasive soot particulates in the engine oil on critical components, including the rocker, rocker shaft and bearing.
  • Modern Exhaust Gas Recirculation (EGR) systems can be a nightmare for diesel engine operators as these systems by their very nature, often contribute to the increased amount of soot produced during the combustion process, as well as increasing the size and abrasive properties of the soot particles.
  • Engine oil, when contaminated with high soot content, basically becomes thicker. The viscosity increases, creating extra rotational and reciprocal load on all moving components which can often reduce cranking speeds (cold-start problems), as well as oil starvation risk at the extreme.
  • Soot and associated sludge in the oil are deposited on most internal engine components. As can be expected, these deposits substantially increase the risk of critical component failure due to lack of adequate lubrication.
  • The extremely abrasive properties of soot grinds protective oil films from important, high-load components, such as cam lobes, followers, and other associated parts.
  • Piston ring grooves accumulate soot and sludge behind the rings over time. This build-up of baked-on hard-carbon particles continues to increase until the piston ring becomes stuck, virtually cemented in the ring groove. The rings can no longer seal effectively against the cylinder walls as compression pressure cannot get behind the rings to force them outward during the compression and combustion strokes. This causes a considerable loss of engine compression, resulting in loss of power, hard start conditions, and excessive engine blow-by. In addition, as the rings cannot squeeze inward either, broken rings are often the result, especially during cold-start conditions.

The solution

The solution to many of these problems is to exercise Pro-active Maintenance™. We’ve discussed this strategy in other posts, but essentially it means to do things differently than we have before. It means to start doing things now to reduce or eliminate many of the effects of these costly issues. We become pro-active…

Here’s how –

  • Effectively and completely remove all existing contaminants from the entire lubrication system. Restore total cleanliness to all oil-wetted components.
  • Reduce or eliminate the likelihood of fuel contamination from faulty fuel injector operation caused by Ultra-low Sulfur diesel.
  • Increase combustion efficiency so that far less abrasive carbon and soot are created during the combustion process.
  • Repeat…
  1. Use Flushing Oil Concentrate at EVERY oil change. When used as recommended, it is the most remarkably effective treatment in removing harmful and performance draining sludge, hard carbon and other contaminants and deposits from oil-wetted engine components. Not only does it safely restore full cleanliness to the entire crankcase, removing all engine sludge, but it also frees up stuck piston rings, restoring compression and oil control. It is entirely safe to use, it contains no corrosive or abrasive solvents. The engine oil stays cleaner and effective much, much longer because residual contaminants are no longer in the lubricating system.
  2. Add ULS Diesel Enhancer directly to the diesel fuel tank. This extremely effective product is the real-life FIX for most modern high-pressure diesel injector problems. ULS Diesel Enhancer cleans fuel pump and injector deposits and disperses contaminants as they form. This highly concentrated product is proven to clean the entire fuel system, bring back correct injector spray patterns, restore power and economy, boost diesel fuel lubrication properties, and provide exceptional anti-rust protection to fuel pumps and injectors.
  3. Add FTC Decarbonizer to the fuel tank, (perfect for gasoline also), to substantially reduce the amount of combustion by-products, such as soot and carbon. FTC Decarbonizer is truly unique! When added to the fuel, it acts as a combustion catalyst to ignite and combust fuel much more easily and effectively. It also literally burns off carbon deposits from combustion areas including ring grooves and cylinder walls, as well as exhaust spaces, especially Diesel Particulate Filters (DPF), at much lower temperatures than otherwise possible, greatly reducing the number of detrimental ‘forced regenerations’.