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Hilux Injectors and Rattles in the Common Rail Engine

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In an earlier post, we covered some general causes of common rail injector failure, but in this post I would like to specifically the Hilux injectors and the causes of failure related to the newer, stricter emission standards and sulphur levels.

Searching the internet will return hundreds of forum and blog articles mentioning Hilux injectors, simply because the Toyota Hilux is the most popular common rail diesel pickup truck worldwide. Most of the information supplied here will be applicable to any late generation common rail diesel engine.

As stated above, low sulphur levels are a necessary component of the latest, stricter diesel emissions standards. But a nasty by-product of that low sulphur is an ugly reduction in lubrication in the common rail system, including Hilux injectors and pumps.

Late generation common rail systems are associated worldwide with a variety of problems, not limited to the Hilux, but more visible simply because of the number of trucks on the road. D4D rattle, premature Hilux injectors and pumps failing, stalling, rapid piston and cylinder deterioration have all been documented in every major common rail manufacturer, some with 50k or less on the odometer.

As mentioned in an earlier post, almost every failure of Hilux injectors and pumps can be traced to fuel, either the quality or the pressure. The incredible pressure that common rail systems operate under causes tremendous heat, which can break down the diesel fuel in the system. Breaking the fuel causes deposits and gumming in the injectors, and this problem is compounded when biodiesel enters the mix, as it degrades at a lower temp than regular fuel.

Higher rail pressures in the new fuel systems also place a huge emphasis on diesel lubrication versus older systems. New common rail systems absolutely demand almost perfect filtration, and just a small amount of contaminant or water will very quickly destroy Hilux injectors and pumps. Anyone who has had the pleasure of purchasing new Hilux or Prado injectors ($2000 per) knows the pain of that unexpected expense. Beyond the costs (expensive) of these items, a sticking injector can cause fuelling problems that will lead to catastrophic engine failure, so any injector rattle should be seen as a big danger sign. Below, you can see the difference between a properly running common rail engine and one with rattle on this Prado D4d.

Failing injectors can sound like anything from a light rattle to an automatic weapon on the battlefield, and it can progress quickly, or as a gradually louder rattle over a long period. The problem could be diesel fuel contamination, or as we mentioned, a lack of lubrication could be sticking the injector. A problem common to Hilux and Prado injectors has to do with an internal seal failure, as discussed by Matt Bailey in a previous post.

New generation common rail injectors are designed with incredibly fine tolerances, and Baileys remanufactured injectors for the Hilux and Prado, sold in a set, are not only as good as the factory replacement injectors, they are better than the OEM, with each set perfectly matched for tolerance. These injectors are literally half of the price of OEM injectors, with twice the warranty, and Baileys offers unbeatable support both before and after the sale.