The 6.5 does not have a very good reputation. Earlier GM diesels have scared people away from the 6.5. The pumps were prone to go out about every 40 to 60 thousand. I think heat is the problem. I removed the center cover (there for looks only) on my 6.5 dually and have not had any problem in 131000. Installed the replacement pump with the green tag because it is supposed to be better. Normal repairs, water pump, alt, belts and change fuel filter ever 10000 miles. Not a real strong engine when compared to the ford p/s and dodge cummins but, fuel mileage may be a little better.