My brother brought over his Dodge Cummins 12 valve for some maintenance the engine oil had about 30,000kms (22,000 miles) on it I don't think Dino oil is supposed to be run that long good thing it is Delo 400. It is not my truck so it is up to him to get the oil changed I keep telling my brother bring the truck over. He has been busy and I work full time. The 12 valve engines are worse than a 2 stroke detroit for leaks everything is bleeding oil. I tried finding a air leak in the fuel system I couldn't find it the return line system is all tight the other fittings are tight. My brother revs the engine past 2000 rpm for any length of time it loads up with air and stalls the motor out so he has to bleed the air out. It happens when he is traveling down he highway it starts missing and stalls. It is a bosch inline pump not the s****y rotary pump. Our cousin is a licensed HD mechanic he can't find where the air leak(s) are coming from. Today I tightened up what ever I could to try stop the oil leaks the back rocker cover boxes are bleeding everywhere. The road draft tube is pouring black oil everywhere. The front of the truck will never get rusty from the 12 valve bleeding oil out. I'am lost on why it is loading up on air in the fuel maybe it is time for a injection pump. The truck has 280,000kms (174,000 miles) it has had the lift pump changed around 230,000kms (143,000 miles) that wasn't cheap the Dodge dealer charged my brother 350 dollars for the pump and 250 dollars to install it. My brother is hoping to get another year out of the truck and get rid of it the transmission is about to go the engine doesn't like to start when its cold. The engine is reaching its lifespan many 12 valve engines around here crap out at 300,000kms (187,000 miles).