@Les1 posted:
Until recently, the Duramax trucks did not put a lift pump in the fuel tank. The last few years, the GM trucks now have one. The FASS system, in addition to the two extra fuel filters, also included a lift pump at the tank. IMHO, this is important, as it eliminates the need for the CP3/CP4 injector pumps to pull fuel from a fuel tank.
As Eric mentions above, stopping water from reaching the pump/injectors is also very important. The current FASS water filter actually stops water from going forward to the stock filter and injector pump. So, I added one to my truck.
Diesel mechanics constantly state, keeping fuel and air clean is extremely important in modern diesel trucks. In commenting about the OP question, I throw my hat in with the above responses. The stock air filter on your PU is an abundant filter. Just change it often. It is very easy to change, so you don't need to pay for someone else to do it.
One final comment. Since the current Ultra low sulfur fuel has less lubrication than regular No 2 fuel, I now add an fuel additive to be safe (Hot Shot).
Congrats on your new truck, Jason!
Thanks for all the good info. I will stay with the OEM filter.
I assume the dealer will check the water separator, and change if necessary when I get the oil changed? Like I previously stated first time diesel owner. I had a diesel tractor and it had a visible water separator that I could empty when full, not sure on this truck.