I've got a 2002 F250 w/7.3 PSD 4x4 about 125,000 on the odometer. I'm having some issues. Lately my fuel economy has dropped and I have noticed a considerable amount of diesel in my coolant reservoir. I do not believe there is any coolant leaking into the engine as there is no noticeable smoke or smell coming from the exhaust. I know that diesel is leaking into the coolant system because as I'm driving the coolant over fill spills out while I'm driving. I have heard some suggestions from other people, but I'm wondering what you guys may think it is? Also how hard is it to replace the injectors in the 7.3? Any special tools needed or can it be done in the driveway?