I just changed my oil at 7500 miles, this is the first oil change, I sent off a sample to Blackstone, I do oil samples every oil change on my Diesel motorhome, I am doing the Ecodiesel just to make sure I dont have coolant in the oil, or bearing material, it's a low cost expense. Being in California adding a GDE won't work they don't sell them here, but after thinking about this, EGR is on every modern Diesel, I think I can deal with that but the PVC crankcase vents appear to add some oil to the intake system, that mixed with the exhaust makes a mess, so I have added a catch can to the PVC hose, so far I have a little exhaust fuzz in the EGR and intake but no oil, so time will tell