Anita posted some time back about how her friendly Isuzu tech had mentioned that some defective EGR valves on our engines may be contributing to internal engine damage.

If the EGR tube has been loose for a long time and since EGR gases actually COOL the combustion gasses, I figured that is going to make the engine run hotter and dirtier, aging and contaminating the oil sooner. The pcv is thrown in for good measure since most people overlook its replacement at the recommended intervals, and it's cheap. A brand name aftermarket replacement should be fine.