Hello everyone, I hope you are all doing well. Sorry to bother you, but I’m hoping someone can help me. I have a Caterpillar 966K loader with a C9.3 engine. I’m experiencing diesel fuel leaking into the engine oil, which causes the oil level to rise. I already replaced the diesel pump and checked the injectors. The machine ran normally for about 190 hours, but then the same problem came back again. Serial no: NGX00352
I’m wondering how you checked the injectors. The only way to be sure is to add some fuel dye in the secondary fuel filter, run it with the valve cover off and check with an infrared torch. But… Doing that is an absolute **** show in a 966K and you’re probably better off replacing 6 injectors. So you replaced the combined HPFP (high pressure fuel pump) and fuel transfer pump assembly? Really, that only leaves the cylinder head as a possible culprit.
Me too. When you checked the injectors did you replace the O-Ring seals.?
Dear all, I decided to continue under the same previous inquiry. As you know, I replaced the pump, and after that, I started having a problem with diesel mixing with the engine oil, causing the oil level to rise. I have carried out maintenance on the injectors around seven times over the past three months, specifically by replacing the control valves. The time interval between each replacement was about 5 to 10 days. During the last time, there was a ticking sound, which indicated that one of the injectors was stuck. So, I removed all of them, and they were repaired just like in the previous times. The strange thing this time was that the engine didn’t start, and I brought in more than 10 technicians, each with a different opinion — some said it was a sensor, others said wiring, and some said the ECM. In the end, one of the technicians installed plugs on the common rail and discovered that the problem came from injectors No. 1 and 4, since only when these two were closed did we get pressure up to 9000. For my part, I replaced the entire set — all six injectors — with a new set, and the engine started immediately, but with issues: The engine sound is very rough, and complete loss of power.