Common Rail Diesel engine problems
Beware of CRD engine rattle at any time!Common Rail Diesel problems can be incredibly expensive to fix!
CRD engines have been recently developed to meet the latest stringent diesel exhaust emission standards and diesel fuel sulphur levels are now very low for the same reason.
But and it’s a BIG BUT, low sulphur fuel happens to compound another problem…lubricity!
Lubricity is the measure of the reduction in friction of a lubricant. At a time when CRD pumps and injectors rely even more on diesel fuel for lubrication, lubricity has actually been reduced! Diesel fuel, without a small biodiesel component, requires lubricity improving additives to prevent excessive engine wear, especially with CRD. Most CRD engines have strict factory limits of 5% or 20% biodiesel component, but NZ legislation currently restricts the limit to 5%. Biodiesels, although likely cheaper than diesel, are not very common in New Zealand.
CRD injection systems are currently internationally associated with widespread problems, including engine rattles, expensive injector and fuel pump failures, injector sticking, engine stalling problems and rapid piston and liner wear. Problems have been documented across a wide range of engine suppliers. Some reports are on engines with way less than 60,000km on the clock.
CRD injectors and fuel pumps run with incredibly fine tolerances and are highly stressed due to enormous pressures often over 200,000kPa (29,000psi), which causes higher diesel fuel temperatures. These high temperatures can degrade diesel fuel resulting in fouling deposits within pumps and injectors. This risk reportedly increases with biodiesel blends, since biodiesel by nature, degrades faster than diesel.
CRD operating pressures also cause higher loadings on equipment, which places a huge demand on the diesel fuel lubricity. Compared to older technology diesel fuel systems, CRD are totally unforgiving when it comes to fuel contamination. Very small amounts of water, or other contaminants in the diesel will wreck CRD pumps and injectors, which are pretty much non-repairable, so it often means new components. $2000 per CRD injector is not uncommon, let alone the labour costs to replace the parts, plus the sometimes forgotten costs of equipment “down time” and "opportunity costs" .. meaning the value of things you can't do because your equipment is not operational and what you could better do with your money.
But the damage doesn’t always stop with injectors and pumps. Sticking injectors can cause gross over-fuelling resulting in melted pistons! Start thinking $10,000 to $20,000 and so treat any injector rattle as a very serious alarm bell.
Injector rattle can sound like noisy valve tappets, or rapid machine gun fire. The injector could be fouled by contaminant, or is seizing due to inadequate lubrication. Excessive fueling could be causing detonation inside the combustion chamber, instead of smooth combustion. Sometimes a rattley, or pinging noise occurs under acceleration from cold, but will disappear after a km or two.
CRD engines are designed with much finer tolerances than older technology, not only within pumps and injectors, but also in piston to liner clearances, making CRD engines much more susceptible to deposits, or the presence of any water or other contamination in the fuel or oil.
Beware of CRD engine rattle at any time .. treat any injector rattle as a very serious alarm bell !
We have recently introduced CRD Fuel ENHANCER a lubricity improving fuel additive, which also has anti-rust and deposit removal properties that will likely solve CRD engine rattles and help stop component failures.