I Am Having To Add Coolent Occasionally And I Canno't See A Leak,when I Remove The Cap On The Resevoir After The Engine Cools There Is Still Some Pressure In The Resevoir.has Anyone Had This Problem?

Check the small hose above the water pump pulley. Mine was seeping past the spring clamps and was getting soft, so I replaced it and put hose clamps on it. Hope I never have to do it again!!

Water pump leaks are fairly common on the duramaxes, but pressure in the system after the engine is cooled down would make me suspect you may have a head gasket leaking which is also a bit common on '01 & '02. For your sake I hope it is the water pump, having headgaskets replaced will be pricey$

Mine does the same thing. I cannot see a leak anywhere. Sometimes I have to add coolent and then it will go a long time and be fine. It is driving me crazy. I do not have a pressure in the overflow tank when cold as far as I can tell. Let us know if you figure it out. I have a 03' with 130,000 miles.