[cucalene]

I wanted to share something with you that I’ve been seeing a lot in the field and it may be useful to some of your customers. We’ve been seeing some issues with vehicles that experience extended idle times and their maintenance intervals. Of course this has been an issue with 6.0Ls because the engine uses oil to hydraulically deliver fuel into the combustion chamber. We’ve seen injector failures caused by poor oil change intervals because of the repetitive pressure the engine oil is exposed to. Now that we’ve moved away from the hydraulic injection system, customers cannot assume that oil change intervals are any less important and assume it is possible to extend drain intervals.



The 6.4L engine is equipped with a Diesel Particulate Filter (DPF). This filter captures the soot in the exhaust stream and allows the engine to comply with 2007 EPA emission regulations. This filter needs to be cleaned or “regenerated” regularly. The regeneration process occurs periodically. During regeneration, fuel is delivered into the combustion chamber via the fuel injectors post piston top dead center. Once the exhaust valves open, the fuel exhaust mixture is forced out of the engine and into a Diesel Oxidation Catalyst (DOC). The DOC catalyzes a reaction and breaks down the soot built up in the DPF. During regeneration, an inherent side effect is that the fuel delivered into the combustion chamber may pass by the piston rings, because fuel has a lower viscosity than oil, and enter the crankcase. Ultimately, this fuel will accumulate in the crankcase and mix with the engine oil. This is expected to happen and vehicles that are maintained properly will not be negatively impacted at all.

Unfortunately, vehicles with higher idle times, thus more regeneration events, may see the oil level rise in the engine due to this. Of course, the oil is not actually multiplying; fuel is just being added to the oil and it appears that the engine oil level is rising. We do not want to see fuel exceeding any more than 6% of the combined mixture. To ensure that this doesn’t happen, customers should change their engine oil at the recommended intervals. Per the Owner’s Manual, the Oil/Oil Filter change interval is 5,000 miles or 200 engine hours (whichever comes first) for vehicles with high idle times. If the oil is changed by hours, customers can easily avoid this potential problem.

Another way to ensure this issue is avoided is to make sure the engines are updated to the most recent calibration per TSB 08-13-02 or 08-13-03 (depending on truck build date). This calibration removes the ability of the engine to regenerate at idle.